Polymers with improved escr for blow molding applications

ABSTRACT

Disclosed herein are ethylene-based polymers having a higher molecular weight component and a lower molecular weight component, and characterized by a density greater than 0.945 g/cm 3 , a melt index less than 1.5 g/10 min, and a ratio of high load melt index to melt index ranging from 40 to 175. These polymers have the processability of chromium-based resins, but with improved stiffness and stress crack resistance, and can be used in blow molding and other end-use applications.

BACKGROUND OF THE INVENTION

Polyolefins such as high density polyethylene (HDPE) homopolymer andcopolymer can be produced using various combinations of catalyst systemsand polymerization processes. Chromium-based catalyst systems can, forexample, produce olefin polymers having good extrusion processibilityand polymer melt strength, typically due to their broad molecular weightdistribution (MWD).

In some end-use applications, such as blow molding, it can be beneficialto have the processibility and melt strength similar to that of anolefin polymer produced from a chromium-based catalyst system, as wellas improvements in toughness, impact strength, and environmental stresscrack resistance (ESCR) at equivalent or higher polymer densities.Accordingly, it is to these ends that the present invention is directed.

SUMMARY OF THE INVENTION

This summary is provided to introduce a selection of concepts in asimplified form that are further described below in the detaileddescription. This summary is not intended to identify required oressential features of the claimed subject matter. Nor is this summaryintended to be used to limit the scope of the claimed subject matter.

The present invention generally relates to ethylene polymers (e.g.,ethylene/α-olefin copolymers) comprising a higher molecular weightcomponent and a lower molecular weight component. In some aspects, theethylene polymer can have a density of greater than or equal to about0.945 g/cm³ (e.g., from about 0.95 to about 0.965), a melt index (MI) ofless than or equal to about 1.5 g/10 min, a ratio of high load meltindex to melt index (HLMI/MI) in a range from about 40 to about 175, anda slope of a plot of the viscosity (Pa-sec) versus shear rate (sec⁻¹) ofthe ethylene polymer at 100 sec⁻¹ in a range from about 0.42 to about0.65. In other aspects, the ethylene polymer can have a density ofgreater than or equal to about 0.945 g/cm³ (e.g., from about 0.95 toabout 0.965), a melt index (MI) of less than or equal to about 1.5 g/10min, a ratio of high load melt index to melt index (HLMI/MI) in a rangefrom about 40 to about 175, a peak molecular weight (Mp) of the highermolecular weight component in a range from about 650,000 to about1,100,000 g/mol, a Mp of the lower molecular weight component in a rangefrom about 40,000 to about 80,000 g/mol, and a ratio of Mw/Mn in a rangefrom about 5 to about 18. These polymers, in further aspects, can becharacterized by an environmental stress crack resistance (ESCR) of atleast 200 hours (10% igepal), and/or an ESCR of at least 1000 hours(100% igepal), and/or a MI in a range from about 0.2 to about 0.8 g/10min, and/or a ratio of HLMI/MI in a range from about 60 to about 160,and/or a density in a range from about 0.955 to about 0.965 g/cm³,and/or a slope of a plot of the viscosity (Pa-sec) versus shear rate(sec⁻¹) of the ethylene polymer at 100 sec⁻¹ in a range from about 0.44to about 0.55, and/or a Mw of the higher molecular weight component in arange from about 825,000 to about 1,500,000 g/mol, and/or a ratio ofMz/Mw of the lower molecular weight component in a range from about 1.5to about 2.8, and/or a ratio of Mw/Mn in a range from about 6 to about15, and/or less than or equal to about 22% of the higher molecularweight component (based on the total weight of the polymer), and/or lessthan about 0.008 long chain branches (LCB) per 1000 total carbon atoms,and/or a non-conventional (flat or reverse) comonomer distribution,and/or a bimodal molecular weight distribution, and/or a zero-shearviscosity in a range from about 1×10⁵ to about 1×10⁷ Pa-sec, and/or azero-shear viscosity in a range from about 2×10⁶ to about 1×10¹² Pa-sec(using the Carreau-Yasuda model with creep adjustment). These ethylenepolymers can be used to produce various articles of manufacture, such asfilms, sheets, pipes, geomembranes, and blow molded bottles.

Both the foregoing summary and the following detailed descriptionprovide examples and are explanatory only. Accordingly, the foregoingsummary and the following detailed description should not be consideredto be restrictive. Further, features or variations may be provided inaddition to those set forth herein. For example, certain aspects andembodiments may be directed to various feature combinations andsub-combinations described in the detailed description.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 presents a plot of the molecular weight distributions of thepolymers of Examples 1-7.

FIG. 2 presents a plot of the molecular weight distribution and shortchain branch distribution of the polymer of Example 2.

FIG. 3 presents a plot of the molecular weight distribution and shortchain branch distribution of the polymer of Example 7.

FIG. 4 presents a rheology plot (viscosity versus shear rate) at 190° C.for the polymers of Examples 1-7.

FIG. 5 presents a rheology plot (viscosity versus shear rate) at 190° C.for the polymers of Examples 1, 7, and 7A-7D.

DEFINITIONS

To define more clearly the terms used herein, the following definitionsare provided. Unless otherwise indicated, the following definitions areapplicable to this disclosure. If a term is used in this disclosure butis not specifically defined herein, the definition from the IUPACCompendium of Chemical Terminology, 2nd Ed (1997), can be applied, aslong as that definition does not conflict with any other disclosure ordefinition applied herein, or render indefinite or non-enabled any claimto which that definition is applied. To the extent that any definitionor usage provided by any document incorporated herein by referenceconflicts with the definition or usage provided herein, the definitionor usage provided herein controls.

While compositions and methods are described herein in terms of“comprising” various components or steps, the compositions and methodscan also “consist essentially of” or “consist of” the various componentsor steps, unless stated otherwise. For example, a catalyst compositionconsistent with aspects of the present invention can comprise;alternatively, can consist essentially of; or alternatively, can consistof; (i) catalyst component I, (ii) catalyst component II, (iii) anactivator, and (iv) optionally, a co-catalyst.

The terms “a,” “an,” “the,” etc., are intended to include pluralalternatives, e.g., at least one, unless otherwise specified. Forinstance, the disclosure of “an activator-support” or “a metallocenecompound” is meant to encompass one, or mixtures or combinations of morethan one, activator-support or metallocene compound, respectively,unless otherwise specified.

Generally, groups of elements are indicated using the numbering schemeindicated in the version of the periodic table of elements published inChemical and Engineering News, 63(5), 27, 1985. In some instances, agroup of elements can be indicated using a common name assigned to thegroup; for example, alkali metals for Group 1 elements, alkaline earthmetals for Group 2 elements, transition metals for Group 3-12 elements,and halogens or halides for Group 17 elements.

For any particular compound disclosed herein, the general structure orname presented is also intended to encompass all structural isomers,conformational isomers, and stereoisomers that can arise from aparticular set of substituents, unless indicated otherwise. Thus, ageneral reference to a compound includes all structural isomers unlessexplicitly indicated otherwise; e.g., a general reference to pentaneincludes n-pentane, 2-methyl-butane, and 2,2-dimethylpropane, while ageneral reference to a butyl group includes an n-butyl group, asec-butyl group, an iso-butyl group, and a tert-butyl group.Additionally, the reference to a general structure or name encompassesall enantiomers, diastereomers, and other optical isomers whether inenantiomeric or racemic forms, as well as mixtures of stereoisomers, asthe context permits or requires. For any particular formula or name thatis presented, any general formula or name presented also encompasses allconformational isomers, regioisomers, and stereoisomers that can arisefrom a particular set of substituents.

The term “substituted” when used to describe a group, for example, whenreferring to a substituted analog of a particular group, is intended todescribe any non-hydrogen moiety that formally replaces a hydrogen inthat group, and is intended to be non-limiting. A group or groups canalso be referred to herein as “unsubstituted” or by equivalent termssuch as “non-substituted,” which refers to the original group in which anon-hydrogen moiety does not replace a hydrogen within that group.Unless otherwise specified, “substituted” is intended to be non-limitingand include inorganic substituents or organic substituents as understoodby one of ordinary skill in the art.

The term “hydrocarbon” whenever used in this specification and claimsrefers to a compound containing only carbon and hydrogen. Otheridentifiers can be utilized to indicate the presence of particulargroups in the hydrocarbon (e.g., halogenated hydrocarbon indicates thepresence of one or more halogen atoms replacing an equivalent number ofhydrogen atoms in the hydrocarbon). The term “hydrocarbyl group” is usedherein in accordance with the definition specified by IUPAC: a univalentgroup formed by removing a hydrogen atom from a hydrocarbon (that is, agroup containing only carbon and hydrogen). Non-limiting examples ofhydrocarbyl groups include alkyl, alkenyl, aryl, and aralkyl groups,amongst other groups.

The term “polymer” is used herein generically to include olefinhomopolymers, copolymers, terpolymers, and so forth. A copolymer isderived from an olefin monomer and one olefin comonomer, while aterpolymer is derived from an olefin monomer and two olefin comonomers.Accordingly, “polymer” encompasses copolymers, terpolymers, etc.,derived from any olefin monomer and comonomer(s) disclosed herein.Similarly, an ethylene polymer would include ethylene homopolymers,ethylene copolymers, ethylene terpolymers, and the like. As an example,an olefin copolymer, such as an ethylene copolymer, can be derived fromethylene and a comonomer, such as 1-butene, 1-hexene, or 1-octene. Ifthe monomer and comonomer were ethylene and 1-hexene, respectively, theresulting polymer can be categorized an as ethylene/1-hexene copolymer.

In like manner, the scope of the term “polymerization” includeshomopolymerization, copolymerization, terpolymerization, etc. Therefore,a copolymerization process can involve contacting one olefin monomer(e.g., ethylene) and one olefin comonomer (e.g., 1-hexene) to produce acopolymer.

The term “co-catalyst” is used generally herein to refer to compoundssuch as aluminoxane compounds, organoboron or organoborate compounds,ionizing ionic compounds, organoaluminum compounds, organozinccompounds, organomagnesium compounds, organolithium compounds, and thelike, that can constitute one component of a catalyst composition, whenused, for example, in addition to an activator-support. The term“co-catalyst” is used regardless of the actual function of the compoundor any chemical mechanism by which the compound may operate.

The terms “chemically-treated solid oxide,” “treated solid oxidecompound,” and the like, are used herein to indicate a solid, inorganicoxide of relatively high porosity, which can exhibit Lewis acidic orBrønsted acidic behavior, and which has been treated with anelectron-withdrawing component, typically an anion, and which iscalcined. The electron-withdrawing component is typically anelectron-withdrawing anion source compound. Thus, the chemically-treatedsolid oxide can comprise a calcined contact product of at least onesolid oxide with at least one electron-withdrawing anion sourcecompound. Typically, the chemically-treated solid oxide comprises atleast one acidic solid oxide compound. The “activator-support” of thepresent invention can be a chemically-treated solid oxide. The terms“support” and “activator-support” are not used to imply these componentsare inert, and such components should not be construed as an inertcomponent of the catalyst composition. The term “activator,” as usedherein, refers generally to a substance that is capable of converting ametallocene component into a catalyst that can polymerize olefins, orconverting a contact product of a metallocene component and a componentthat provides an activatable ligand (e.g., an alkyl, a hydride) to themetallocene, when the metallocene compound does not already comprisesuch a ligand, into a catalyst that can polymerize olefins. This term isused regardless of the actual activating mechanism. Illustrativeactivators include activator-supports, aluminoxanes, organoboron ororganoborate compounds, ionizing ionic compounds, and the like.Aluminoxanes, organoboron or organoborate compounds, and ionizing ioniccompounds generally are referred to as activators if used in a catalystcomposition in which an activator-support is not present. If thecatalyst composition contains an activator-support, then thealuminoxane, organoboron or organoborate, and ionizing ionic materialsare typically referred to as co-catalysts.

The term “metallocene” as used herein describes compounds comprising atleast one η³ to η⁵-cycloalkadienyl-type moiety, wherein η³ toη⁵-cycloalkadienyl moieties include cyclopentadienyl ligands, indenylligands, fluorenyl ligands, and the like, including partially saturatedor substituted derivatives or analogs of any of these. Possiblesubstituents on these ligands may include H, therefore this inventioncomprises ligands such as tetrahydroindenyl, tetrahydrofluorenyl,octahydrofluorenyl, partially saturated indenyl, partially saturatedfluorenyl, substituted partially saturated indenyl, substitutedpartially saturated fluorenyl, and the like. In some contexts, themetallocene is referred to simply as the “catalyst,” in much the sameway the term “co-catalyst” is used herein to refer to, for example, anorganoaluminum compound.

The terms “catalyst composition,” “catalyst mixture,” “catalyst system,”and the like, do not depend upon the actual product or compositionresulting from the contact or reaction of the initial components of thedisclosed or claimed catalyst composition/mixture/system, the nature ofthe active catalytic site, or the fate of the co-catalyst, themetallocene compound(s), or the activator (e.g., activator-support),after combining these components. Therefore, the terms “catalystcomposition,” “catalyst mixture,” “catalyst system,” and the like,encompass the initial starting components of the composition, as well aswhatever product(s) may result from contacting these initial startingcomponents, and this is inclusive of both heterogeneous and homogenouscatalyst systems or compositions. The terms “catalyst composition,”“catalyst mixture,” “catalyst system,” and the like, can be usedinterchangeably throughout this disclosure.

The term “contact product” is used herein to describe compositionswherein the components are contacted together in any order, in anymanner, and for any length of time. For example, the components can becontacted by blending or mixing. Further, contacting of any componentcan occur in the presence or absence of any other component of thecompositions described herein. Combining additional materials orcomponents can be done by any suitable method. Further, the term“contact product” includes mixtures, blends, solutions, slurries,reaction products, and the like, or combinations thereof. Although“contact product” can include reaction products, it is not required forthe respective components to react with one another. Similarly, the term“contacting” is used herein to refer to materials which can be blended,mixed, slurried, dissolved, reacted, treated, or otherwise contacted insome other manner.

Although any methods, devices, and materials similar or equivalent tothose described herein can be used in the practice or testing of theinvention, the typical methods, devices and materials are hereindescribed.

All publications and patents mentioned herein are incorporated herein byreference for the purpose of describing and disclosing, for example, theconstructs and methodologies that are described in the publications,which might be used in connection with the presently describedinvention. The publications discussed throughout the text are providedsolely for their disclosure prior to the filing date of the presentapplication. Nothing herein is to be construed as an admission that theinventors are not entitled to antedate such disclosure by virtue ofprior invention.

Applicants disclose several types of ranges in the present invention.When Applicants disclose or claim a range of any type, Applicants'intent is to disclose or claim individually each possible number thatsuch a range could reasonably encompass, including end points of therange as well as any sub-ranges and combinations of sub-rangesencompassed therein. For example, when the Applicants disclose or claima chemical moiety having a certain number of carbon atoms, Applicants'intent is to disclose or claim individually every possible number thatsuch a range could encompass, consistent with the disclosure herein. Forexample, the disclosure that a moiety is a C₁ to C₁₈ hydrocarbyl group,or in alternative language, a hydrocarbyl group having from 1 to 18carbon atoms, as used herein, refers to a moiety that can have 1, 2, 3,4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, or 18 carbon atoms, aswell as any range between these two numbers (for example, a C₁ to C₈hydrocarbyl group), and also including any combination of ranges betweenthese two numbers (for example, a C₂ to C₄ and a C₁₂ to C₁₆ hydrocarbylgroup).

Similarly, another representative example follows for the ratio of Mw/Mnof an ethylene polymer consistent with aspects of this invention. By adisclosure that the ratio of Mw/Mn can be in a range from about 5 toabout 18, Applicants intend to recite that the ratio of Mw/Mn can be anyratio in the range and, for example, can be equal to about 5, about 6,about 7, about 8, about 9, about 10, about 11, about 12, about 13, about14, about 15, about 16, about 17, or about 18. Additionally, the ratioof Mw/Mn can be within any range from about 5 to about 18 (for example,from about 6 to about 16), and this also includes any combination ofranges between about 5 and about 18 (for example, the Mw/Mn ratio can bein a range from about 5 to about 8, or from about 12 to about 18).Likewise, all other ranges disclosed herein should be interpreted in amanner similar to these examples.

Applicants reserve the right to proviso out or exclude any individualmembers of any such group, including any sub-ranges or combinations ofsub-ranges within the group, that can be claimed according to a range orin any similar manner, if for any reason Applicants choose to claim lessthan the full measure of the disclosure, for example, to account for areference that Applicants may be unaware of at the time of the filing ofthe application. Further, Applicants reserve the right to proviso out orexclude any individual substituents, analogs, compounds, ligands,structures, or groups thereof, or any members of a claimed group, if forany reason Applicants choose to claim less than the full measure of thedisclosure, for example, to account for a reference that Applicants maybe unaware of at the time of the filing of the application.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed generally to higher densityethylene-based polymers having improved toughness, impact resistance,and environmental stress crack resistance (ESCR). Articles produced fromthese ethylene-based polymers, for example, using film/sheet extrusion,profile extrusion, or blow molding, are suitable for a variety ofend-use applications.

Ethylene Polymers

Generally, the polymers disclosed herein are ethylene-based polymers, orethylene polymers, encompassing homopolymers of ethylene as well ascopolymers, terpolymers, etc., of ethylene and at least one olefincomonomer. Comonomers that can be copolymerized with ethylene often canhave from 3 to 20 carbon atoms in their molecular chain. For example,typical comonomers can include, but are not limited to, propylene,1-butene, 2-butene, 3-methyl-1-butene, isobutylene, 1-pentene,2-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-hexene, 2-hexene,3-hexene, 3-ethyl-1-hexene, 1-heptene, 2-heptene, 3-heptene, the fournormal octenes (e.g., 1-octene), the four normal nonenes, the fivenormal decenes, and the like, or mixtures of two or more of thesecompounds. In an aspect, the olefin comonomer can comprise a C₃-C₁₈olefin; alternatively, the olefin comonomer can comprise a C₃-C₁₀olefin; alternatively, the olefin comonomer can comprise a C₄-C₁₀olefin; alternatively, the olefin comonomer can comprise a C₃-C₁₀α-olefin; or alternatively, the olefin comonomer can comprise a C₄-C₁₀α-olefin.

According to another aspect of this invention, the olefin monomer cancomprise ethylene, and the olefin comonomer can include, but is notlimited to, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene,1-octene, and the like, or combinations thereof. In yet another aspect,the comonomer can comprise 1-butene, 1-hexene, 1-octene, or anycombination thereof. In still another aspect, the comonomer can comprise1-butene; alternatively, 1-hexene; or alternatively, 1-octene.Typically, the amount of the comonomer, based on the total weight ofmonomer (ethylene) and comonomer, can be in a range from about 0.01 toabout 10 wt. %, from about 0.1 to about 5 wt. %, from about 0.15 toabout 5 wt. %, from about 0.15 to about 2 wt. %, or from about 0.1 toabout 1 wt. %.

In some aspects, the ethylene polymer of this invention can be anethylene/α-olefin copolymer. For example, the ethylene polymer can be anethylene/1-butene copolymer, an ethylene/1-hexene copolymer, or anethylene/1-octene copolymer. In particular aspects contemplated herein,the ethylene polymer can be an ethylene/1-hexene copolymer.

Certain aspects of this invention are directed to improved polyolefinresins for blow molding applications, as compared to conventional resinsproduced using chromium-based catalyst systems. Conventionalchromium-based resins for blow molding applications generally have abroad MWD, acceptable die swell, high melt strength, and overallexcellent processability on a wide range of blow molding machinery.Notwithstanding these benefits, improvements in toughness, impactstrength, stiffness, and ESCR are desired, while maintainingsubstantially no melt fracture, substantially no gels that can causepinholes, substantially no char or black specs, substantially no smokeand odor, and good trimmability. Ethylene polymers described herein, incertain aspects, can provide a unique combination of the ease ofprocessing typically associated with conventional chromium-based resins(e.g., acceptable die swell, high melt strength, etc.), along withimprovements in toughness, stiffness (e.g., higher density), impactstrength, and ESCR over conventional chromium-based resins. Suchimprovements can result in blow molded parts or articles with longerlifetimes, and may allow processors the opportunity to downgauge orthin-wall the blow molded parts or articles, resulting in decreasedresin usage and cost reduction.

The ethylene polymers (e.g., ethylene copolymers) described herein canhave a lower molecular weight component and a higher molecular weightcomponent. An illustrative and non-limiting example of an ethylenepolymer of the present invention can have a density of greater than orequal to about 0.945 g/cm³ (e.g., from about 0.95 to about 0.965), amelt index (MI) of less than or equal to about 1.5 g/10 min, a ratio ofhigh load melt index to melt index (HLMI/MI) in a range from about 40 toabout 175, and a slope of a plot of the viscosity (Pa-sec) versus shearrate (sec⁻¹) of the ethylene polymer at 100 sec⁻¹ in a range from about0.42 to about 0.65. Another illustrative and non-limiting example of anethylene polymer of the present invention can have a density of greaterthan or equal to about 0.945 g/cm³ (e.g., from about 0.95 to about0.965), a melt index (MI) of less than or equal to about 1.5 g/10 min, aratio of high load melt index to melt index (HLMI/MI) in a range fromabout 40 to about 175, a peak molecular weight (Mp) of the highermolecular weight component in a range from about 650,000 to about1,100,000 g/mol, a Mp of the lower molecular weight component in a rangefrom about 40,000 to about 80,000 g/mol, and a ratio of Mw/Mn in a rangefrom about 5 to about 18. These illustrative and non-limiting examplesof ethylene polymers consistent with the present invention also can haveany of the polymer properties listed below and in any combination.

Ethylene polymers (homopolymers, copolymers, etc.) of this inventiongenerally can have a melt index (MI) from 0 to about 1.5 g/10 min. Meltindices in the range from 0 to about 1.2, from 0 to about 1, from about0.05 to about 1.2, or from about 0.1 to about 1 g/10 min, arecontemplated in other aspects of this invention. For example, a polymerof the present invention can have a MI in a range from about 0.1 toabout 0.9, from about 0.2 to about 0.9, or from about 0.2 to about 0.8g/10 min.

Consistent with certain aspects of this invention, ethylene polymersdescribed herein can have a high load melt index (HLMI) in a range fromabout 15 to about 100, from about 20 to about 100, from about 15 toabout 90, or from about 20 to about 90 g/10 min. In further aspects,ethylene polymers described herein can have a HLMI in a range from about20 to about 85, from about 35 to about 100, from about 15 to about 75,or from about 30 to about 80 g/10 min.

Ethylene polymers in accordance with this invention can have a ratio ofHLMI/MI in a range from about 40 to about 175, from about 50 to about175, or from about 50 to about 150. Other suitable ranges for HLMI/MIcan include, but are not limited to, from about 60 to about 160, fromabout 55 to about 140, from about 45 to about 145, or from about 50 toabout 130, and the like.

The densities of ethylene-based polymers disclosed herein often aregreater than or equal to about 0.945 g/cm³, for example, greater than orequal to about 0.95, or greater than or equal to about 0.955 g/cm³, andoften can range up to about 0.968 g/cm³. Yet, in particular aspects, thedensity can be in a range from about 0.945 to about 0.965, from about0.95 to about 0.965, from about 0.95 to about 0.962, from about 0.955 toabout 0.965, or from about 0.957 to about 0.963 g/cm³.

Generally, polymers in aspects of the present invention have low levelsof long chain branching, with typically less than about 0.01 long chainbranches (LCB) per 1000 total carbon atoms, and similar in LCB contentto polymers shown, for example, in U.S. Pat. Nos. 7,517,939, 8,114,946,and 8,383,754, which are incorporated herein by reference in theirentirety. In other aspects, the number of LCB per 1000 total carbonatoms can be less than about 0.008, less than about 0.007, less thanabout 0.005, or less than about 0.003 LCB per 1000 total carbon atoms.

In certain aspects, the disclosed ethylene polymers can have improvedenvironmental stress crack resistance (ESCR) over comparable polymers(e.g., equivalent density, melt index, molecular weight, etc.) producedusing a chromium-based catalyst system. ESCR testing and test resultsdisclosed herein are from ASTM D1693, condition B, either 10% igepal or100% igepal: the 10% igepal ESCR test is a much more stringent test thanESCR testing conducted using the 100% igepal solution. In some aspects,the ethylene polymers described herein can have an ESCR (using 100%igepal) of at least 400 hours, at least 600 hours, at least 1,000 hours,at least 1,200 hours, at least 1,500 hours, or at least 2,000 hours, andoften can range as high as 2,500 to 4,000 hours. The ESCR test istypically stopped after a certain number of hours is reached, and giventhe long duration of the test, the upper limit of ESCR (in hours) isgenerally not determined. In other aspects, the ethylene polymersdescribed herein can have an ESCR (using 10% igepal) of at least 100hours, at least 150 hours, at least 200 hours, at least 250 hours, atleast 400 hours, or at least 500 hours, and often can range as high as1,000 to 2,000 hours.

Ethylene copolymers described herein can, in some aspects, have anon-conventional (flat or reverse) comonomer distribution, generally,the higher molecular weight components of the polymer have equal to orhigher comonomer incorporation than the lower molecular weightcomponents. Typically, there is flat or increasing comonomerincorporation with increasing molecular weight. In one aspect, thenumber of short chain branches (SCB) per 1000 total carbon atoms of thepolymer at Mw is greater than or equal to the number at Mn. In anotheraspect, the number of short chain branches (SCB) per 1000 total carbonatoms of the polymer at Mz is greater than or equal to the number at Mw.In yet another aspect, the number of SCB per 1000 total carbon atoms ofthe polymer at Mz is greater than or equal to the number at Mn. In stillanother aspect, the number of short chain branches (SCB) per 1000 totalcarbon atoms of the polymer at a molecular weight of 10⁶ is greater thanor equal to the number at a molecular weight of 10⁵.

In an aspect, ethylene polymers described herein can have a ratio ofMw/Mn, or the polydispersity index, in a range from about 5 to about 18,from about 5 to about 15, from about 5 to about 14, from about 6 toabout 18, from about 6 to about 16, or from about 6 to about 15. Inanother aspect, ethylene polymers described herein can have a Mw/Mn in arange from about 7 to about 18, from about 7 to about 15, from about 8to about 16, or from about 8 to about 14.

In an aspect, ethylene polymers described herein can have a ratio ofMz/Mw in a range from about 5 to about 12, from about 5.5 to about 12,from about 5.5 to about 11, or from about 6 to about 12. In anotheraspect, ethylene polymers described herein can have a Mz/Mw in a rangefrom about 6 to about 10, or from about 6.5 to about 9.5.

In an aspect, ethylene polymers described herein can have aweight-average molecular weight (Mw) in a range from about 150,000 toabout 375,000, from about 150,000 to about 350,000, from about 150,000to about 325,000, or from about 150,000 to about 300,000 g/mol. Inanother aspect, ethylene polymers described herein can have a Mw in arange from about 175,000 to about 425,000, from about 175,000 to about375,000, from about 175,000 to about 350,000, or from about 175,000 toabout 300,000 g/mol.

In an aspect, ethylene polymers described herein can have anumber-average molecular weight (Mn) in a range from about 10,000 toabout 40,000, from about 12,000 to about 40,000, or from about 15,000 toabout 40,000 g/mol. In another aspect, ethylene polymers describedherein can have a Mn in a range from about 12,000 to about 45,000, fromabout 12,000 to about 35,000, from about 15,000 to about 35,000, fromabout 15,000 to about 30,000, or from about 18,000 to about 25,000g/mol.

In an aspect, ethylene polymers described herein can have a z-averagemolecular weight (Mz) in a range from about 800,000 to about 4,000,000,from about 900,000 to about 4,000,000, or from about 1,000,000 to about4,000,000 g/mol. In another aspect, ethylene polymers described hereincan have a Mz in a range from about 900,000 to about 3,500,000, fromabout 1,000,000 to about 3,500,000, from about 1,000,000 to about3,000,000, or from about 900,000 to about 2,500,000 g/mol.

In an aspect, ethylene polymers described herein can have a CY-aparameter at 190° C. in a range from about 0.02 to about 0.3, from about0.04 to about 0.2, from about 0.04 to about 0.18, from about 0.06 toabout 0.3, or from about 0.06 to about 0.18. The CY-a parameter wasdetermined at 190° C. using the using the Carreau-Yasuda model withcreep adjustment, as described herein. In some aspects, ethylenepolymers described herein can have a zero-shear viscosity at 190° C. ofgreater than or equal to about 1×10⁵, greater than or equal to about2×10⁵, in a range from about 1×10⁵ to about 1×10⁷, or in a range fromabout 2×10⁵ to about 1×10⁷ Pa-sec. In these and other aspects, ethylenepolymers described herein can have a zero-shear viscosity of greaterthan or equal to about 1×10⁶, greater than or equal to about 2×10⁶, in arange from about 1×10⁶ to about 1×10¹⁴, or in a range from about 2×10⁶to about 1×10¹² Pa-sec, using the Carreau Yasuda model with creepadjustment. While not wishing to be bound by theory, applicants believethat a higher zero-shear viscosity may correlate with a higher polymermelt strength (e.g., better melt strength and processability in blowmolding).

Unexpectedly, Applicants determined that the die swell of an ethylenepolymer, for example, in a blow molding process, correlates with arheological slope parameter, i.e., the slope of a plot of the viscosity(Pa-sec) versus shear rate (sec⁻¹) at 100 sec⁻¹ for the ethylene polymerat 190° C. In an aspect, the ethylene polymer can have a slope of a plotof the viscosity (Pa-sec) versus shear rate (sec⁻¹) at 100 sec⁻¹ and190° C. (the rheological slope parameter) in a range from about 0.42 toabout 0.65, such as, for example, from about 0.42 to about 0.6, fromabout 0.42 to about 0.55, from about 0.44 to about 0.65, from about 0.44to about 0.55, from about 0.42 to about 0.5, from about 0.44 to about0.5, from about 0.45 to about 0.6, or from about 0.45 to about 0.5. Therheological slope parameter is determined from the viscosity datameasured at 190° C.

Generally, ethylene polymers consistent with certain aspects of theinvention often can have a bimodal molecular weight distribution (asdetermined using gel permeation chromatography (GPC) or other suitableanalytical technique). Often, in a bimodal molecular weightdistribution, there is a valley between the peaks, and the peaks can beseparated or deconvoluted. Typically, a bimodal molecular weightdistribution can be characterized as having an identifiable highmolecular weight component (or distribution) and an identifiable lowmolecular weight component (or distribution). Illustrative unimodal MWDcurves and bimodal MWD curves are shown in U.S. Pat. No. 8,383,754,incorporated herein by reference in its entirety.

In an aspect, the ethylene polymer described herein can be a reactorproduct (e.g., a single reactor product), for example, not apost-reactor blend of two polymers, for instance, having differentmolecular weight characteristics. As one of skill in the art wouldreadily recognize, physical blends of two different polymer resins canbe made, but this necessitates additional processing and complexity notrequired for a reactor product.

As described herein, ethylene polymers (e.g., ethylene/α-olefincopolymers) can have a lower molecular weight component and a highermolecular weight component. The molecular weight characteristics andrelative amounts of these lower and higher molecular weight componentsare determined by deconvoluting the composite (overall polymer)molecular weight distribution (e.g., determined using gel permeationchromatography). The amount of the higher molecular weight component,based on the weight of the total polymer, is not limited to anyparticular range. Generally, however, the amount of the higher molecularweight component can less than or equal to about 35%, less than or equalto about 30%, less than or equal to about 25%, less than or equal toabout 22%, or less than or equal to about 20%. Suitable non-limitingranges for the amount of the higher molecular weight component, based onthe weight of the total polymer, include from about 5 to about 30%, fromabout 6 to about 35%, from about 4 to about 25%, from about 5 to about22%, from about 5 to about 20%, from about 5 to about 18%, from about 6to about 25%, from about 6 to about 22%, from about 6 to about 20%, orfrom about 6 to about 18%.

In accordance with aspects of this invention, the higher molecularweight component can have a Mp in a range from about 650,000 to about1,100,000, from about 700,000 to about 1,100,000, from about 650,000 toabout 1,000,000, from about 700,000 to about 1,000,000, or from about725,000 to about 975,000 g/mol. Additionally or alternatively, thehigher molecular weight component can have a Mw in a range from about825,000 to about 1,500,000, from about 825,000 to about 1,300,000, fromabout 850,000 to about 1,350,000, or from about 850,000 to about1,250,000 g/mol. Additionally or alternatively, the higher molecularweight component can have a Mn in a range from about 175,000 to about700,000, from about 175,000 to about 600,000, from about 200,000 toabout 650,000, from about 200,000 to about 600,000, or from about225,000 to about 600,000 g/mol. Additionally or alternatively, thehigher molecular weight component can have a ratio of Mz/Mw of less thanor equal to about 2.5, less than or equal to about 2.2, in a range fromabout 1.5 to about 2.5, or in a range from about 1.5 to about 2.2.

In accordance with aspects of this invention, the lower molecular weightcomponent can have a Mp in a range from about 40,000 to about 75,000,from about 45,000 to about 80,000, from about 45,000 to about 75,000,from about 45,000 to about 70,000, or from about 40,000 to about 80,000g/mol. Additionally or alternatively, the lower molecular weightcomponent can have a Mw in a range from about 45,000 to about 85,000,from about 45,000 to about 80,000, from about 50,000 to about 80,000, orfrom about 55,000 to about 80,000 g/mol. Additionally or alternatively,the lower molecular weight component can have a Mn in a range from about8,000 to about 35,000, from about 10,000 to about 35,000, from about10,000 to about 30,000, or from about 12,000 to about 25,000 g/mol.Additionally or alternatively, the lower molecular weight component canhave a ratio of Mz/Mw of less than or equal to about 2.8, less than orequal to about 2.5, in a range from about 1.5 to about 2.8, in a rangefrom about 1.6 to about 2.5, in a range from about 1.6 to about 2.4, orin a range from about 1.6 to about 2.2.

In accordance with some aspects of this invention, the ethylene polymeris not peroxide treated or modified, and certain representative polymerproperties are disclosed hereinabove. In other aspects of thisinvention, the ethylene polymer has been peroxide treated or modifiedfrom a base resin, and the peroxide treated ethylene polymer and/or thebase resin has the representative polymer properties disclosedhereinabove. In these aspects, the ethylene polymer can be produced froma base resin via a process comprising contacting the base resin with aperoxide compound at a temperature sufficient to generate peroxidegroups at about 10 to about 400 ppm of peroxide groups based on theweight of the base resin. In some aspects, the amount of peroxide groupsin the peroxide compound, based on the weight of the base resin, can bein a range from about 10 to about 300 ppm, from about 10 to about 250ppm, from about 10 to about 100 ppm, from about 10 to about 50 ppm, fromabout 15 to about 350 ppm, from about 15 to about 250 ppm, or from about20 to about 150 ppm.

The peroxide compound can be any compound containing one or moreperoxide (O—O) groups, suitable examples of which can include, but arenot limited to, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, dicumylperoxide, t-butyl cumyl peroxide,n-butyl-4,4′-di(t-butylperoxy)valerate, and the like.

In an aspect, the step of contacting the base resin with the peroxidecompound can comprise melt processing a blend (or mixture) of the baseresin and the peroxide compound at any suitable melt processingtemperature, such as, for example, a temperature in a range from about120 to about 300° C., a temperature in a range from about 150 to about250° C., a temperature in a range from about 175 to about 225° C., andso forth. The appropriate temperature may depend upon the composition ofthe peroxide compound and the temperature at which it generates peroxidegroups. Prior to contacting the peroxide compound, the base resin can bein any suitable form including, for example, fluff, powder, granulate,pellet, solution, slurry, emulsion, and the like. Similarly, theperoxide compound can be in solid form, in solution, or in a slurry. Oneparticular method uses a resin-based masterbatch of the peroxidecompound, and contacts the base resin after it has been melted.

The present invention is not limited to any particular method ofcontacting and melt processing the base resin and the peroxide compound.Various methods of mixing and/or compounding can be employed, as wouldbe recognized by those of skill in the art. In one aspect, the meltprocessing of the base resin and the peroxide compound can be performedin a twin screw extrusion system. In another aspect, the melt processingof the base resin and the peroxide compound can be performed in a singlescrew extrusion system.

As described herein, certain properties of the ethylene polymer beforeand after peroxide treatment can be generally in the same ranges. Incontrast, increasing levels of peroxide addition during peroxidetreatment typically increases the zero-shear viscosity and therelaxation time, and decreases the CY-a parameter, ESCR, and therheological slope parameter. Hence, peroxide treatment can be used tomodify certain properties of the base ethylene polymer, if desired, tobetter match the processing characteristics of chromium-based resins(e.g., zero-shear viscosity, die swell, etc.).

Articles and Products

Articles of manufacture can be formed from, and/or can comprise, theethylene polymers of this invention and, accordingly, are encompassedherein. For example, articles which can comprise ethylene polymers ofthis invention can include, but are not limited to, an agriculturalfilm, an automobile part, a bottle, a drum, a fiber or fabric, a foodpackaging film or container, a food service article, a fuel tank, ageomembrane, a household container, a liner, a molded product, a medicaldevice or material, a pipe, a sheet or tape, a toy, and the like.Various processes can be employed to form these articles. Non-limitingexamples of these processes include injection molding, blow molding,rotational molding, film extrusion, sheet extrusion, profile extrusion,thermoforming, and the like. Additionally, additives and modifiers areoften added to these polymers in order to provide beneficial polymerprocessing or end-use product attributes. Such processes and materialsare described in Modern Plastics Encyclopedia, Mid-November 1995 Issue,Vol. 72, No. 12; and Film Extrusion Manual—Process, Materials,Properties, TAPPI Press, 1992; the disclosures of which are incorporatedherein by reference in their entirety. In some aspects of thisinvention, an article of manufacture can comprise any of ethylenepolymers described herein, and the article of manufacture can be a blowmolded article.

Applicants also contemplate a method for forming or preparing an articleof manufacture comprising any ethylene polymer disclosed herein. Forinstance, a method can comprise (i) contacting a catalyst compositionwith ethylene and an optional olefin comonomer under polymerizationconditions in a polymerization reactor system to produce an ethylenepolymer, wherein the catalyst composition can comprise catalystcomponent I, catalyst component II, an activator (e.g., anactivator-support comprising a solid oxide treated with anelectron-withdrawing anion), and an optional co-catalyst (e.g., anorganoaluminum compound); and (ii) forming an article of manufacturecomprising the ethylene polymer. The forming step can comprise blending,melt processing, extruding, molding (e.g., blow molding), orthermoforming, and the like, including combinations thereof.

Catalyst Systems and Polymerization Processes

In accordance with some aspects of the present invention, the ethylenepolymer (and/or the base resin) can be produced using a Ziegler-Nattacatalyst system. In accordance with other aspects of the presentinvention, the ethylene polymer (and/or the base resin) can be producedusing a metallocene-based catalyst system. In accordance with furtheraspects of the present invention, the ethylene polymer (and/or the baseresin) can be produced using a dual metallocene-based catalyst system.In these aspects, catalyst component I can comprise an unbridgedmetallocene compound, for instance, an unbridged zirconium or hafniumbased metallocene compound containing two cyclopentadienyl groups, twoindenyl groups, or a cyclopentadienyl and an indenyl group. Catalystcomponent II can comprise a bridged metallocene compound, for instance,a bridged zirconium or hafnium based metallocene compound with acyclopentadienyl group and a fluorenyl group, and with an alkenylsubstituent on the bridging group and/or on the cyclopentadienyl group.

Generally, catalyst component I can comprise an unbridged zirconium orhafnium based metallocene compound and/or an unbridged zirconium and/orhafnium based dinuclear metallocene compound. In one aspect, forinstance, catalyst component I can comprise an unbridged zirconium orhafnium based metallocene compound containing two cyclopentadienylgroups, two indenyl groups, or a cyclopentadienyl and an indenyl group.In another aspect, catalyst component I can comprise an unbridgedzirconium or hafnium based metallocene compound containing twocyclopentadienyl groups. In yet another aspect, catalyst component I cancomprise an unbridged zirconium or hafnium based metallocene compoundcontaining two indenyl groups. In still another aspect, catalystcomponent I can comprise an unbridged zirconium or hafnium basedmetallocene compound containing a cyclopentadienyl and an indenyl group.

In some aspects, catalyst component I can comprise an unbridgedzirconium based metallocene compound containing two cyclopentadienylgroups, two indenyl groups, or a cyclopentadienyl and an indenyl group,while in other aspects, catalyst component I can comprise a dinuclearunbridged metallocene compound with an alkenyl linking group.

Catalyst component I can comprise, in particular aspects of thisinvention, an unbridged metallocene compound having formula (I):

Within formula (I), M, Cp^(A), Cp^(B), and each X are independentelements of the unbridged metallocene compound. Accordingly, theunbridged metallocene compound having formula (I) can be described usingany combination of M, Cp^(A), Cp^(B), and X disclosed herein.

Unless otherwise specified, formula (I) above, any other structuralformulas disclosed herein, and any metallocene complex, compound, orspecies disclosed herein are not designed to show stereochemistry orisomeric positioning of the different moieties (e.g., these formulas arenot intended to display cis or trans isomers, or R or Sdiastereoisomers), although such compounds are contemplated andencompassed by these formulas and/or structures.

In accordance with aspects of this invention, the metal in formula (I),M, can be Ti, Zr, or Hf. In one aspect, for instance, M can be Zr or Hf,while in another aspect, M can be Ti; alternatively, M can be Zr; oralternatively, M can be Hf.

Each X in formula (I) independently can be a monoanionic ligand. In someaspects, suitable monoanionic ligands can include, but are not limitedto, H (hydride), BH₄, a halide, a C₁ to C₃₆ hydrocarbyl group, a C₁ toC₃₆ hydrocarboxy group, a C₁ to C₃₆ hydrocarbylaminyl group, a C₁ to C₃₆hydrocarbylsilyl group, a C₁ to C₃₆ hydrocarbylaminylsilyl group, —OBR¹₂, or —OSO₂R¹, wherein R¹ is a C₁ to C₃₆ hydrocarbyl group. It iscontemplated that each X can be either the same or a differentmonoanionic ligand.

In one aspect, each X independently can be H, BH₄, a halide (e.g., F,Cl, Br, etc.), a C₁ to C₁₈ hydrocarbyl group, a C₁ to C₁₈ hydrocarboxygroup, a C₁ to C₁₈ hydrocarbylaminyl group, a C₁ to C₁₈ hydrocarbylsilylgroup, or a C₁ to C₁₈ hydrocarbylaminylsilyl group. Alternatively, eachX independently can be H, BH₄, a halide, OBR¹ ₂, or OSO₂R¹, wherein R¹is a C₁ to C₁₈ hydrocarbyl group. In another aspect, each Xindependently can be H, BH₄, a halide, a C₁ to C₁₂ hydrocarbyl group, aC₁ to C₁₂ hydrocarboxy group, a C₁ to C₁₂ hydrocarbylaminyl group, a C₁to C₁₂ hydrocarbylsilyl group, a C₁ to C₁₂ hydrocarbylaminylsilyl group,OBR¹ ₂, or OSO₂R¹, wherein R¹ is a C₁ to C₁₂ hydrocarbyl group. Inanother aspect, each X independently can be H, BH₄, a halide, a C₁ toC₁₀ hydrocarbyl group, a C₁ to C₁₀ hydrocarboxy group, a C₁ to C₁₀hydrocarbylaminyl group, a C₁ to C₁₀ hydrocarbylsilyl group, a C₁ to C₁₀hydrocarbylaminylsilyl group, OBR¹ ₂, or OSO₂R¹, wherein R¹ is a C₁ toC₁₀ hydrocarbyl group. In yet another aspect, each X independently canbe H, BH₄, a halide, a C₁ to C₈ hydrocarbyl group, a C₁ to C₈hydrocarboxy group, a C₁ to C₈ hydrocarbylaminyl group, a C₁ to C₈hydrocarbylsilyl group, a C₁ to C₈ hydrocarbylaminylsilyl group, OBR¹ ₂,or OSO₂R¹, wherein R¹ is a C₁ to C₈ hydrocarbyl group. In still anotheraspect, each X independently can be a halide or a C₁ to C₁₈ hydrocarbylgroup. For example, each X can be Cl.

In one aspect, each X independently can be H, BH₄, a halide, or a C₁ toC₃₆ hydrocarbyl group, hydrocarboxy group, hydrocarbylaminyl group,hydrocarbylsilyl group, or hydrocarbylaminylsilyl group, while inanother aspect, each X independently can be H, BH₄, or a C₁ to C₁₈hydrocarboxy group, hydrocarbylaminyl group, hydrocarbylsilyl group, orhydrocarbylaminylsilyl group. In yet another aspect, each Xindependently can be a halide; alternatively, a C₁ to C₁₈ hydrocarbylgroup; alternatively, a C₁ to C₁₈ hydrocarboxy group; alternatively, aC₁ to C₁₈ hydrocarbylaminyl group; alternatively, a C₁ to C₁₈hydrocarbylsilyl group; or alternatively, a C₁ to C₁₈hydrocarbylaminylsilyl group. In still another aspect, each X can be H;alternatively, F; alternatively, Cl; alternatively, Br; alternatively,I; alternatively, BH₄; alternatively, a C₁ to C₁₈ hydrocarbyl group;alternatively, a C₁ to C₁₈ hydrocarboxy group; alternatively, a C₁ toC₁₈ hydrocarbylaminyl group; alternatively, a C₁ to C₁₈ hydrocarbylsilylgroup; or alternatively, a C₁ to C₁₈ hydrocarbylaminylsilyl group.

Each X independently can be, in some aspects, H, a halide, methyl,phenyl, benzyl, an alkoxy, an aryloxy, acetylacetonate, formate,acetate, stearate, oleate, benzoate, an alkylaminyl, a dialkylaminyl, atrihydrocarbylsilyl, or a hydrocarbylaminylsilyl; alternatively, H, ahalide, methyl, phenyl, or benzyl; alternatively, an alkoxy, an aryloxy,or acetylacetonate; alternatively, an alkylaminyl or a dialkylaminyl;alternatively, a trihydrocarbylsilyl or hydrocarbylaminylsilyl;alternatively, H or a halide; alternatively, methyl, phenyl, benzyl, analkoxy, an aryloxy, acetylacetonate, an alkylaminyl, or a dialkylaminyl;alternatively, H; alternatively, a halide; alternatively, methyl;alternatively, phenyl; alternatively, benzyl; alternatively, an alkoxy;alternatively, an aryloxy; alternatively, acetylacetonate;alternatively, an alkylaminyl; alternatively, a dialkylaminyl;alternatively, a trihydrocarbylsilyl; or alternatively, ahydrocarbylaminylsilyl. In these and other aspects, the alkoxy, aryloxy,alkylaminyl, dialkylaminyl, trihydrocarbylsilyl, andhydrocarbylaminylsilyl can be a C₁ to C₃₆, a C₁ to C₁₈, a C₁ to C₁₂, ora C₁ to C₈ alkoxy, aryloxy, alkylaminyl, dialkylaminyl,trihydrocarbylsilyl, and hydrocarbylaminylsilyl.

Moreover, each X independently can be, in certain aspects, a halide or aC₁ to C₁₈ hydrocarbyl group; alternatively, a halide or a C₁ to C₈hydrocarbyl group; alternatively, F, Cl, Br, I, methyl, benzyl, orphenyl; alternatively, Cl, methyl, benzyl, or phenyl; alternatively, aC₁ to C₁₈ alkoxy, aryloxy, alkylaminyl, dialkylaminyl,trihydrocarbylsilyl, or hydrocarbylaminylsilyl group; alternatively, aC₁ to C₈ alkoxy, aryloxy, alkylaminyl, dialkylaminyl,trihydrocarbylsilyl, or hydrocarbylaminylsilyl group; or alternatively,methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl,decyl, ethenyl, propenyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl,nonenyl, decenyl, phenyl, tolyl, benzyl, naphthyl, trimethylsilyl,triisopropylsilyl, triphenylsilyl, or allyldimethylsilyl.

In formula (I), Cp^(A) and Cp^(B) independently can be a substituted orunsubstituted cyclopentadienyl or indenyl group. In one aspect, Cp^(A)and Cp^(B) independently can be an unsubstituted cyclopentadienyl orindenyl group. Alternatively, Cp^(A) and Cp^(B) independently can be asubstituted indenyl or cyclopentadienyl group, for example, having up to5 substituents.

If present, each substituent on Cp^(A) and Cp^(B) independently can beH, a halide, a C₁ to C₃₆ hydrocarbyl group, a C₁ to C₃₆ halogenatedhydrocarbyl group, a C₁ to C₃₆ hydrocarboxy group, or a C₁ to C₃₆hydrocarbylsilyl group. Importantly, each substituent on Cp^(A) and/orCp^(B) can be either the same or a different substituent group.Moreover, each substituent can be at any position on the respectivecyclopentadienyl or indenyl ring structure that conforms with the rulesof chemical valence. In an aspect, the number of substituents on Cp^(A)and/or on Cp^(B) and/or the positions of each substituent on Cp^(A)and/or on Cp^(B) are independent of each other. For instance, two ormore substituents on Cp^(A) can be different, or alternatively, eachsubstituent on Cp^(A) can be the same. Additionally or alternatively,two or more substituents on Cp^(B) can be different, or alternatively,all substituents on Cp^(B) can be the same. In another aspect, one ormore of the substituents on Cp^(A) can be different from the one or moreof the substituents on Cp^(B), or alternatively, all substituents onboth Cp^(A) and/or on Cp^(B) can be the same. In these and otheraspects, each substituent can be at any position on the respectivecyclopentadienyl or indenyl ring structure. If substituted, Cp^(A)and/or Cp^(B) independently can have one substituent, two substituents,three substituents, four substituents, and so forth.

In formula (I), each substituent on Cp^(A) and/or on Cp^(B)independently can be H, a halide, a C₁ to C₃₆ hydrocarbyl group, a C₁ toC₃₆ halogenated hydrocarbyl group, a C₁ to C₃₆ hydrocarboxy group, or aC₁ to C₃₆ hydrocarbylsilyl group. In some aspects, each substituentindependently can be H; alternatively, a halide; alternatively, a C₁ toC₁₈ hydrocarbyl group; alternatively, a C₁ to C₁₈ halogenatedhydrocarbyl group; alternatively, a C₁ to C₁₈ hydrocarboxy group;alternatively, a C₁ to C₁₈ hydrocarbylsilyl group; alternatively, a C₁to C₁₂ hydrocarbyl group or a C₁ to C₁₂ hydrocarbylsilyl group; oralternatively, a C₁ to C₈ alkyl group or a C₃ to C₈ alkenyl group. Thehalide, C₁ to C₃₆ hydrocarbyl group, C₁ to C₃₆ hydrocarboxy group, andC₁ to C₃₆ hydrocarbylsilyl group which can be a substituent on Cp^(A)and/or on Cp^(B) in formula (I) can be any halide, C₁ to C₃₆ hydrocarbylgroup, C₁ to C₃₆ hydrocarboxy group, and C₁ to C₃₆ hydrocarbylsilylgroup described herein (e.g., as pertaining to X in formula (I)). Asubstituent on Cp^(A) and/or on Cp^(B) in formula (I) can be, in certainaspects, a C₁ to C₃₆ halogenated hydrocarbyl group, where thehalogenated hydrocarbyl group indicates the presence of one or morehalogen atoms replacing an equivalent number of hydrogen atoms in thehydrocarbyl group. The halogenated hydrocarbyl group often can be ahalogenated alkyl group, a halogenated alkenyl group, a halogenatedcycloalkyl group, a halogenated aryl group, or a halogenated aralkylgroup. Representative and non-limiting halogenated hydrocarbyl groupsinclude pentafluorophenyl, trifluoromethyl (CF₃), and the like.

As a non-limiting example, if present, each substituent on Cp^(A) and/orCp^(B) independently can be H, Cl, CF₃, a methyl group, an ethyl group,a propyl group, a butyl group (e.g., t-Bu), a pentyl group, a hexylgroup, a heptyl group, an octyl group, a nonyl group, a decyl group, anethenyl group, a propenyl group, a butenyl group, a pentenyl group, ahexenyl group, a heptenyl group, an octenyl group, a nonenyl group, adecenyl group, a phenyl group, a tolyl group (or other substituted arylgroup), a benzyl group, a naphthyl group, a trimethylsilyl group, atriisopropylsilyl group, a triphenylsilyl group, or anallyldimethylsilyl group; alternatively, H; alternatively, Cl;alternatively, CF₃; alternatively, a methyl group; alternatively, anethyl group; alternatively, a propyl group; alternatively, a butylgroup; alternatively, a pentyl group; alternatively, a hexyl group;alternatively, a heptyl group; alternatively, an octyl group, a nonylgroup; alternatively, a decyl group; alternatively, an ethenyl group;alternatively, a propenyl group; alternatively, a butenyl group;alternatively, a pentenyl group; alternatively, a hexenyl group;alternatively, a heptenyl group; alternatively, an octenyl group;alternatively, a nonenyl group; alternatively, a decenyl group;alternatively, a phenyl group; alternatively, a tolyl group;alternatively, a benzyl group; alternatively, a naphthyl group;alternatively, a trimethylsilyl group; alternatively, atriisopropylsilyl group; alternatively, a triphenylsilyl group; oralternatively, an allyldimethylsilyl group.

Illustrative and non-limiting examples of unbridged metallocenecompounds having formula (I) and/or suitable for use as catalystcomponent I can include the following compounds (Ph=phenyl):

and the like, as well as combinations thereof

Catalyst component I is not limited solely to unbridged metallocenecompounds such as described above, or to suitable unbridged metallocenecompounds disclosed in U.S. Pat. Nos. 7,199,073, 7,226,886, 7,312,283,and 7,619,047, which are incorporated herein by reference in theirentirety. For example, catalyst component I can comprise an unbridgedzirconium and/or hafnium based dinuclear metallocene compound. In oneaspect, catalyst component I can comprise an unbridged zirconium basedhomodinuclear metallocene compound. In another aspect, catalystcomponent I can comprise an unbridged hafnium based homodinuclearmetallocene compound. In yet another aspect, catalyst component I cancomprise an unbridged zirconium and/or hafnium based heterodinuclearmetallocene compound (i.e., dinuclear compound with two hafniums, or twozirconiums, or one zirconium and one hafnium). Catalyst component I cancomprise unbridged dinuclear metallocenes such as those described inU.S. Pat. Nos. 7,919,639 and 8,080,681, the disclosures of which areincorporated herein by reference in their entirety. Illustrative andnon-limiting examples of dinuclear metallocene compounds suitable foruse as catalyst component I can include the following compounds:

and the like, as well as combinations thereof

Generally, catalyst component II can comprise a bridged metallocenecompound. In one aspect, for instance, catalyst component II cancomprise a bridged zirconium or hafnium based metallocene compound. Inanother aspect, catalyst component II can comprise a bridged zirconiumor hafnium based metallocene compound with an alkenyl substituent. Inyet another aspect, catalyst component II can comprise a bridgedzirconium or hafnium based metallocene compound with an alkenylsubstituent and a fluorenyl group. In still another aspect, catalystcomponent II can comprise a bridged zirconium or hafnium basedmetallocene compound with a cyclopentadienyl group and a fluorenylgroup, and with an alkenyl substituent on the bridging group and/or onthe cyclopentadienyl group.

In some aspects, catalyst component II can comprise a bridgedmetallocene compound having an aryl group substituent on the bridginggroup, while in other aspects, catalyst component II can comprise adinuclear bridged metallocene compound with an alkenyl linking group.

Catalyst component II can comprise, in particular aspects of thisinvention, a bridged metallocene compound having formula (II):

Within formula (II), M, Cp, R^(X), R^(Y), E, and each X are independentelements of the bridged metallocene compound. Accordingly, the bridgedmetallocene compound having formula (II) can be described using anycombination of M, Cp, R^(X), R^(Y), E, and X disclosed herein.

The selections for M and each X in formula (II) are the same as thosedescribed herein above for formula (I). In formula (II), Cp can be asubstituted cyclopentadienyl, indenyl, or fluorenyl group. In oneaspect, Cp can be a substituted cyclopentadienyl group, while in anotheraspect, Cp can be a substituted indenyl group.

In some aspects, Cp can contain no additional substituents, e.g., otherthan bridging group E, discussed further herein below. In other aspects,Cp can be further substituted with one substituent, two substituents,three substituents, four substituents, and so forth. If present, eachsubstituent on Cp independently can be H, a halide, a C₁ to C₃₆hydrocarbyl group, a C₁ to C₃₆ halogenated hydrocarbyl group, a C₁ toC_(36 hydrocarboxy group, or a C) ₁ to C₃₆ hydrocarbylsilyl group.Importantly, each substituent on Cp can be either the same or adifferent substituent group. Moreover, each substituent can be at anyposition on the respective cyclopentadienyl, indenyl, or fluorenyl ringstructure that conforms with the rules of chemical valence. In general,any substituent on Cp, independently, can be H or any halide, C₁ to C₃₆hydrocarbyl group, C₁ to C₃₆ halogenated hydrocarbyl group, C₁ to C₃₆hydrocarboxy group, or C₁ to C₃₆ hydrocarbylsilyl group described herein(e.g., as pertaining to substituents on Cp^(A) and Cp^(B) in formula(I)).

In one aspect, for example, each substituent on Cp independently can bea C₁ to C₁₂ hydrocarbyl group or a C₁ to C₁₂ hydrocarbylsilyl group. Inanother aspect, each substituent on Cp independently can be a C₁ to C₈alkyl group or a C₃ to C₈ alkenyl group. In yet another aspect, eachsubstituent on Cp^(C) independently can be H, Cl, CF₃, a methyl group,an ethyl group, a propyl group, a butyl group, a pentyl group, a hexylgroup, a heptyl group, an octyl group, a nonyl group, a decyl group, anethenyl group, a propenyl group, a butenyl group, a pentenyl group, ahexenyl group, a heptenyl group, an octenyl group, a nonenyl group, adecenyl group, a phenyl group, a tolyl group, a benzyl group, a naphthylgroup, a trimethylsilyl group, a triisopropylsilyl group, atriphenylsilyl group, or an allyldimethylsilyl group.

Similarly, R^(X) and R^(Y) in formula (II) independently can be H or anyhalide, C₁ to C₃₆ hydrocarbyl group, C₁ to C₃₆ halogenated hydrocarbylgroup, C₁ to C₃₆ hydrocarboxy group, or C₁ to C₃₆ hydrocarbylsilyl groupdisclosed herein (e.g., as pertaining to substituents on Cp^(A) andCp^(B) in formula (I)). In one aspect, for example, R^(X) and R^(Y)independently can be H or a C₁ to C₁₂ hydrocarbyl group. In anotheraspect, R^(X) and R^(Y) independently can be a C₁ to C₁₀ hydrocarbylgroup. In yet another aspect, R^(X) and R^(Y) independently can be H,Cl, CF₃, a methyl group, an ethyl group, a propyl group, a butyl group(e.g., t-Bu), a pentyl group, a hexyl group, a heptyl group, an octylgroup, a nonyl group, a decyl group, an ethenyl group, a propenyl group,a butenyl group, a pentenyl group, a hexenyl group, a heptenyl group, anoctenyl group, a nonenyl group, a decenyl group, a phenyl group, a tolylgroup, a benzyl group, a naphthyl group, a trimethylsilyl group, atriisopropylsilyl group, a triphenylsilyl group, or anallyldimethylsilyl group, and the like. In still another aspect, R^(X)and R^(Y) independently can be a methyl group, an ethyl group, a propylgroup, a butyl group, a pentyl group, a hexyl group, a heptyl group, anoctyl group, a nonyl group, a decyl group, an ethenyl group, a propenylgroup, a butenyl group, a pentenyl group, a hexenyl group, a heptenylgroup, an octenyl group, a nonenyl group, a decenyl group, a phenylgroup, a tolyl group, or a benzyl group.

Bridging group E in formula (II) can be (i) a bridging group having theformula >E^(A)R^(A)R^(B), wherein E^(A) can be C, Si, or Ge, and R^(A)and R^(B) independently can be H or a C₁ to C₁₈ hydrocarbyl group; (ii)a bridging group having the formula —CR^(C)R^(D)—CR^(E)R^(F)—, whereinR^(C), R^(D), R^(E), and R^(F) independently can be H or a C₁ to C₁₈hydrocarbyl group; or (iii) a bridging group having the formula—SiR^(G)R^(H)-E⁵R^(I)R^(J)—, wherein E⁵ can be C or Si, and R^(G),R^(H), R^(I), and R^(J) independently can be H or a C₁ to C₁₈hydrocarbyl group.

In the first option, the bridging group E can have the formula>E^(A)R^(A)R^(B), wherein E^(A) can be C, Si, or Ge, and R^(A) and R^(B)independently can be H or any C₁ to C₁₈ hydrocarbyl group disclosedherein. In some aspects of this invention, R^(A) and R^(B) independentlycan be a C₁ to C₁₂ hydrocarbyl group; alternatively, R^(A) and R^(B)independently can be a C₁ to C₈ hydrocarbyl group; alternatively, R^(A)and R^(B) independently can be a phenyl group, a C₁ to C₈ alkyl group,or a C₃ to C₈ alkenyl group; alternatively, R^(A) and R^(B)independently can be a methyl group, an ethyl group, a propyl group, abutyl group, a pentyl group, a hexyl group, a heptyl group, an octylgroup, a nonyl group, a decyl group, an ethenyl group, a propenyl group,a butenyl group, a pentenyl group, a hexenyl group, a heptenyl group, anoctenyl group, a nonenyl group, a decenyl group, a phenyl group, acyclohexylphenyl group, a naphthyl group, a tolyl group, or a benzylgroup; or alternatively, R^(A) and R^(B) independently can be a methylgroup, an ethyl group, a propyl group, a butyl group, a pentyl group, ahexyl group, a propenyl group, a butenyl group, a pentenyl group, ahexenyl group, a phenyl group, or a benzyl group. In these and otheraspects, R^(A) and R^(B) can be either the same or different.

In the second option, the bridging group E can have the formula—CR^(C)R^(D)—CR^(E)R^(F), wherein R^(C), R^(D), R^(E), and R^(F)independently can be H or any C₁ to C₁₅ hydrocarbyl group disclosedherein. For instance, R^(C), R^(D), R^(E), and R^(F) independently canbe H or a methyl group.

In the third option, the bridging group E can have the formula—SiR^(G)R^(H)-E⁵R^(I)R^(J)—, wherein E⁵ can be C or Si, and R^(G),R^(H), R^(I), and R^(J) independently can be H or any C₁ to C₁₈hydrocarbyl group disclosed herein. For instance, E⁵ can be Si, andR^(G), R^(H), R^(J), and R^(I) independently can be H or a methyl group.

Illustrative and non-limiting examples of bridged metallocene compoundshaving formula (II) and/or suitable for use as catalyst component II caninclude the following compounds (Me=methyl, Ph=phenyl; t-Bu=tert-butyl):

and the like, as well as combinations thereof

Further examples of bridged metallocene compounds having formula (II)and/or suitable for use as catalyst component II can include, but arenot limited to, the following compounds:

and the like, as well as combinations thereof

Catalyst component II is not limited solely to the bridged metallocenecompounds such as described above. Other suitable bridged metallocenecompounds are disclosed in U.S. Pat. Nos. 7,026,494, 7,041,617,7,226,886, 7,312,283, 7,517,939, and 7,619,047, which are incorporatedherein by reference in their entirety.

According to an aspect of this invention, the weight ratio of catalystcomponent I to catalyst component II in the catalyst composition can bein a range from about 10:1 to about 1:10, from about 8:1 to about 1:8,from about 5:1 to about 1:5, from about 4:1 to about 1:4, from about 3:1to about 1:3; from about 2:1 to about 1:2, from about 1.5:1 to about1:1.5, from about 1.25:1 to about 1:1.25, or from about 1.1:1 to about1:1.1.

Typically, the dual metallocene-based catalyst system contains anactivator. For example, the catalyst system can contain anactivator-support, an aluminoxane compound, an organoboron ororganoborate compound, an ionizing ionic compound, and the like, or anycombination thereof. The catalyst system can contain one or more thanone activator.

In one aspect, the catalyst system can comprise an aluminoxane compound,an organoboron or organoborate compound, an ionizing ionic compound, andthe like, or a combination thereof. Examples of such activators aredisclosed in, for instance, U.S. Pat. Nos. 3,242,099, 4,794,096,4,808,561, 5,576,259, 5,807,938, 5,919,983, and 8,114,946, thedisclosures of which are incorporated herein by reference in theirentirety. In another aspect, the catalyst system can comprise analuminoxane compound. In yet another aspect, the catalyst system cancomprise an organoboron or organoborate compound. In still anotheraspect, the catalyst system can comprise an ionizing ionic compound.

In other aspects, the catalyst system can comprise an activator-support,for example, an activator-support comprising a solid oxide treated withan electron-withdrawing anion. Examples of such materials are disclosedin, for instance, U.S. Pat. Nos. 7,294,599, 7,601,665, 7,884,163,8,309,485, and 8,623,973, which are incorporated herein by reference intheir entirety. For instance, the activator-support can comprisefluorided alumina, chlorided alumina, bromided alumina, sulfatedalumina, fluorided silica-alumina, chlorided silica-alumina, bromidedsilica-alumina, sulfated silica-alumina, fluorided silica-zirconia,chlorided silica-zirconia, bromided silica-zirconia, sulfatedsilica-zirconia, fluorided silica-titania, fluorided silica-coatedalumina, sulfated silica-coated alumina, or phosphated silica-coatedalumina, and the like, as well as any combination thereof. In someaspects, the activator-support can comprise a fluorided solid oxideand/or a sulfated solid oxide.

The present invention can employ catalyst compositions containingcatalyst component I, catalyst component II, an activator (one or morethan one), and optionally, a co-catalyst. When present, the co-catalystcan include, but is not limited to, metal alkyl, or organometal,co-catalysts, with the metal encompassing boron, aluminum, and the like.Optionally, the catalyst systems provided herein can comprise aco-catalyst, or a combination of co-catalysts. For instance, alkyl boronand/or alkyl aluminum compounds often can be used as co-catalysts insuch catalyst systems. Representative boron compounds can include, butare not limited to, tri-n-butyl borane, tripropylborane, triethylborane,and the like, and this include combinations of two or more of thesematerials. While not being limited thereto, representative aluminumcompounds (e.g., organoaluminum compounds) can include,trimethylaluminum, triethylaluminum, tri-n-propylaluminum,tri-n-butylaluminum, triisobutylaluminum, tri-n-hexylaluminum,tri-n-octylaluminum, diisobutylaluminum hydride, diethylaluminumethoxide, diethylaluminum chloride, and the like, as well as anycombination thereof.

The ethylene polymers (and/or base resins) can be produced using anysuitable olefin polymerization process using various types ofpolymerization reactors, polymerization reactor systems, andpolymerization reaction conditions. As used herein, “polymerizationreactor” includes any polymerization reactor capable of polymerizing(inclusive of oligomerizing) olefin monomers and comonomers (one or morethan one comonomer) to produce homopolymers, copolymers, terpolymers,and the like. The various types of polymerization reactors include thosethat can be referred to as a batch reactor, slurry reactor, gas-phasereactor, solution reactor, high pressure reactor, tubular reactor,autoclave reactor, and the like, or combinations thereof. Thepolymerization conditions for the various reactor types are well knownto those of skill in the art. Gas phase reactors can comprise fluidizedbed reactors or staged horizontal reactors. Slurry reactors can comprisevertical or horizontal loops. High pressure reactors can compriseautoclave or tubular reactors. Reactor types can include batch orcontinuous processes. Continuous processes can use intermittent orcontinuous product discharge. Polymerization reactor systems andprocesses also can include partial or full direct recycle of unreactedmonomer, unreacted comonomer, and/or diluent.

A polymerization reactor system can comprise a single reactor ormultiple reactors (2 reactors, more than 2 reactors, etc.) of the sameor different type. For instance, the polymerization reactor system cancomprise a slurry reactor, a gas-phase reactor, a solution reactor, or acombination of two or more of these reactors. Production of polymers inmultiple reactors can include several stages in at least two separatepolymerization reactors interconnected by a transfer device making itpossible to transfer the polymers resulting from the firstpolymerization reactor into the second reactor. The desiredpolymerization conditions in one of the reactors can be different fromthe operating conditions of the other reactor(s). Alternatively,polymerization in multiple reactors can include the manual transfer ofpolymer from one reactor to subsequent reactors for continuedpolymerization. Multiple reactor systems can include any combinationincluding, but not limited to, multiple loop reactors, multiple gasphase reactors, a combination of loop and gas phase reactors, multiplehigh pressure reactors, or a combination of high pressure with loopand/or gas phase reactors. The multiple reactors can be operated inseries, in parallel, or both.

According to one aspect, the polymerization reactor system can compriseat least one loop slurry reactor comprising vertical or horizontalloops. Monomer, diluent, catalyst, and comonomer can be continuously fedto a loop reactor where polymerization occurs. Generally, continuousprocesses can comprise the continuous introduction of monomer/comonomer,a catalyst, and a diluent into a polymerization reactor and thecontinuous removal from this reactor of a suspension comprising polymerparticles and the diluent. Reactor effluent can be flashed to remove thesolid polymer from the liquids that comprise the diluent, monomer and/orcomonomer. Various technologies can be used for this separation stepincluding, but not limited to, flashing that can include any combinationof heat addition and pressure reduction, separation by cyclonic actionin either a cyclone or hydrocyclone, or separation by centrifugation.

A typical slurry polymerization process (also known as the particle formprocess) is disclosed, for example, in U.S. Pat. Nos. 3,248,179,4,501,885, 5,565,175, 5,575,979, 6,239,235, 6,262,191, and 6,833,415,each of which is incorporated herein by reference in its entirety.

Suitable diluents used in slurry polymerization include, but are notlimited to, the monomer being polymerized and hydrocarbons that areliquids under reaction conditions. Examples of suitable diluentsinclude, but are not limited to, hydrocarbons such as propane,cyclohexane, isobutane, n-butane, n-pentane, isopentane, neopentane, andn-hexane. Some loop polymerization reactions can occur under bulkconditions where no diluent is used. An example is polymerization ofpropylene monomer as disclosed in U.S. Pat. No. 5,455,314, which isincorporated by reference herein in its entirety.

According to yet another aspect, the polymerization reactor system cancomprise at least one gas phase reactor (e.g., a fluidized bed reactor).Such reactor systems can employ a continuous recycle stream containingone or more monomers continuously cycled through a fluidized bed in thepresence of the catalyst under polymerization conditions. A recyclestream can be withdrawn from the fluidized bed and recycled back intothe reactor. Simultaneously, polymer product can be withdrawn from thereactor and new or fresh monomer can be added to replace the polymerizedmonomer. Such gas phase reactors can comprise a process for multi-stepgas-phase polymerization of olefins, in which olefins are polymerized inthe gaseous phase in at least two independent gas-phase polymerizationzones while feeding a catalyst-containing polymer formed in a firstpolymerization zone to a second polymerization zone. One type of gasphase reactor is disclosed in U.S. Pat. Nos. 5,352,749, 4,588,790, and5,436,304, each of which is incorporated by reference in its entiretyherein.

According to still another aspect, the polymerization reactor system cancomprise a high pressure polymerization reactor, e.g., can comprise atubular reactor or an autoclave reactor. Tubular reactors can haveseveral zones where fresh monomer, initiators, or catalysts are added.Monomer can be entrained in an inert gaseous stream and introduced atone zone of the reactor. Initiators, catalysts, and/or catalystcomponents can be entrained in a gaseous stream and introduced atanother zone of the reactor. The gas streams can be intermixed forpolymerization. Heat and pressure can be employed appropriately toobtain optimal polymerization reaction conditions.

According to yet another aspect, the polymerization reactor system cancomprise a solution polymerization reactor wherein the monomer/comonomerare contacted with the catalyst composition by suitable stirring orother means. A carrier comprising an inert organic diluent or excessmonomer can be employed. If desired, the monomer/comonomer can bebrought in the vapor phase into contact with the catalytic reactionproduct, in the presence or absence of liquid material. Thepolymerization zone can be maintained at temperatures and pressures thatwill result in the formation of a solution of the polymer in a reactionmedium. Agitation can be employed to obtain better temperature controland to maintain uniform polymerization mixtures throughout thepolymerization zone. Adequate means are utilized for dissipating theexothermic heat of polymerization.

The polymerization reactor system can further comprise any combinationof at least one raw material feed system, at least one feed system forcatalyst or catalyst components, and/or at least one polymer recoverysystem. Suitable reactor systems can further comprise systems forfeedstock purification, catalyst storage and preparation, extrusion,reactor cooling, polymer recovery, fractionation, recycle, storage,loadout, laboratory analysis, and process control. Depending upon thedesired properties of the olefin polymer, hydrogen can be added to thepolymerization reactor as needed (e.g., continuously, pulsed, etc.).

Polymerization conditions that can be controlled for efficiency and toprovide desired polymer properties can include temperature, pressure,and the concentrations of various reactants. Polymerization temperaturecan affect catalyst productivity, polymer molecular weight, andmolecular weight distribution. Various polymerization conditions can beheld substantially constant, for example, for the production of aparticular grade of ethylene polymer. A suitable polymerizationtemperature can be any temperature below the de-polymerizationtemperature according to the Gibbs Free energy equation. Typically, thisincludes from about 60° C. to about 280° C., for example, or from about60° C. to about 120° C., depending upon the type of polymerizationreactor. In some reactor systems, the polymerization temperaturegenerally can be within a range from about 70° C. to about 90° C., orfrom about 75° C. to about 85° C.

Suitable pressures will also vary according to the reactor andpolymerization type. The pressure for liquid phase polymerizations in aloop reactor typically can be less than 1000 psig. The pressure for gasphase polymerization can be in the 200 to 500 psig range. High pressurepolymerization in tubular or autoclave reactors generally can beconducted at about 20,000 to 75,000 psig. Polymerization reactors alsocan be operated in a supercritical region occurring at generally highertemperatures and pressures. Operation above the critical point of apressure/temperature diagram (supercritical phase) can offer advantages.

EXAMPLES

The invention is further illustrated by the following examples, whichare not to be construed in any way as imposing limitations to the scopeof this invention. Various other aspects, embodiments, modifications,and equivalents thereof which, after reading the description herein, maysuggest themselves to one of ordinary skill in the art without departingfrom the spirit of the present invention or the scope of the appendedclaims.

Melt index (MI, g/10 min) was determined in accordance with ASTM D1238at 190° C. with a 2,160 gram weight, and high load melt index (HLMI,g/10 min) was determined in accordance with ASTM D1238 at 190° C. with a21,600 gram weight. Polymer density was determined in grams per cubiccentimeter (g/cm³) on a compression molded sample, cooled at about 15°C. per hour, and conditioned for about 40 hours at room temperature inaccordance with ASTM D1505 and ASTM D4703. ESCR was determined inaccordance with ASTM D1693, condition B, with 10% igepal or 100% igepal.

Molecular weights and molecular weight distributions were obtained usinga PL-GPC 220 (Polymer Labs, an Agilent Company) system equipped with aIR4 detector (Polymer Char, Spain) and three Styragel HMW-6E GPC columns(Waters, MA) running at 145° C. The flow rate of the mobile phase1,2,4-trichlorobenzene (TCB) containing 0.5 g/L2,6-di-t-butyl-4-methylphenol (BHT) was set at 1 mL/min, and polymersolution concentrations were in the range of 1.0-1.5 mg/mL, depending onthe molecular weight. Sample preparation was conducted at 150° C. fornominally 4 hr with occasional and gentle agitation, before thesolutions were transferred to sample vials for injection. An injectionvolume of about 200 μL was used. The integral calibration method wasused to deduce molecular weights and molecular weight distributionsusing a Chevron Phillips Chemical Company's HDPE polyethylene resin,MARLEX® BHB5003, as the broad standard. The integral table of the broadstandard was pre-determined in a separate experiment with SEC-MALS. Mnis the number-average molecular weight, Mw is the weight-averagemolecular weight, Mz is the z-average molecular weight, My is theviscosity-average molecular weight, and Mp is the peak molecular weight(location, in molecular weight, of the highest point of each componentof the molecular weight distribution curve).

Melt rheological characterizations were performed as follows.Small-strain (10%) oscillatory shear measurements were performed on aRheometrics Scientific, Inc. ARES rheometer using parallel-plategeometry. All rheological tests were performed at 190° C. The complexviscosity |η*| versus frequency (ω) data were then curve fitted usingthe modified three parameter Carreau-Yasuda (CY) empirical model toobtain the zero shear viscosity—η₀, characteristic viscous relaxationtime—τ_(η), and the breadth parameter—α. The simplified Carreau-Yasuda(CY) empirical model is as follows.

${{{\eta^{*}(\omega)}} = \frac{\eta_{0}}{\left\lbrack {1 + \left( {\tau_{\eta}\omega} \right)^{a}} \right\rbrack^{{({1 - n})}/a}}},$

wherein:

-   -   |η*(ω)|=magnitude of complex shear viscosity;    -   η₀=zero shear viscosity;    -   τ_(η)=viscous relaxation time (Tau(η));    -   α=“breadth” parameter (CY-a parameter);    -   n=fixes the final power law slope, fixed at 2/11; and    -   ω=angular frequency of oscillatory shearing deformation.

Details of the significance and interpretation of the CY model andderived parameters may be found in: C. A. Hieber and H. H. Chiang,Rheol. Acta, 28, 321 (1989); C. A. Hieber and H. H. Chiang, Polym. Eng.Sci., 32, 931 (1992); and R. B. Bird, R. C. Armstrong and O. Hasseger,Dynamics of Polymeric Liquids, Volume 1, Fluid Mechanics, 2nd Edition,John Wiley & Sons (1987); each of which is incorporated herein byreference in its entirety.

A creep adjustment was used to extend the low frequency range ofrheological characterization to 10⁻⁴ sec⁻¹. In the creep test, aconstant shear stress σ₀ was applied to the specimen and the shearstrain γ was recorded as a function of creep time t. Although thetime-dependent data generated by the creep and creep recovery tests lookdifferent from the frequency-dependent data measured in the dynamicfrequency sweep test, as long as the measurements are performed in thelinear viscoelastic regime, these two experimental data sets contain thesame rheological information, so that the time-dependent creepcompliance data can be transformed into the frequency-dependent dynamicdata, and thus the long time creep measurement can supplement the lowfrequency data of the dynamic frequency sweep measurement.

The generalized Voigt model was used for modeling the time-dependentcreep compliance J(t)=γ(t)/σ₀ in terms of a discrete spectrum J_(k) ofretardation times τ_(k) and zero shear rate viscosity η₀,

${J(t)} = {{\sum\limits_{k = 1}^{N}\; {J_{k}\left( {1 - ^{{- t}/\tau_{k}}} \right)}} + {\frac{t}{\eta_{0}}.}}$

If the discrete retardation spectrum accurately describes the compliancedata, the theory of linear viscoelasticity permits a quantitativedescription of other types of experimental data, for example, thestorage and the loss compliance calculated as

${{J^{\prime}(\omega)} = {\sum\limits_{k = 1}^{N}\; {J_{k}\frac{1}{1 + {\omega^{2}\tau_{k}^{2}}}}}},{{J^{''}(\omega)} = {\frac{1}{\omega \; \eta_{0}} + {\sum\limits_{k = 1}^{N}\; {J_{k}{\frac{\omega \; \tau_{k}}{1 + {\omega^{2}\tau_{k}^{2}}}.}}}}}$

From the relationship between the complex modulus and the complexcompliance, the storage and loss modulus of dynamic frequency sweep datacan be obtained as

${{G^{\prime}(\omega)} = \frac{J^{\prime}(\omega)}{\left\lbrack {J^{\prime}(\omega)} \right\rbrack^{2} + \left\lbrack {J^{''}(\omega)} \right\rbrack^{2}}},{{G^{\prime}(\omega)} = {\frac{J^{''}(\omega)}{\left\lbrack {J^{\prime}(\omega)} \right\rbrack^{2} + \left\lbrack {J^{''}(\omega)} \right\rbrack^{2}}.}}$

As a simple numerical approach to obtain the discrete spectrum ofretardation times, the Microsoft Excel Solver tool can be used byminimizing the following objective function O.

$O = {\sum\limits_{i = 1}^{N}\; {\frac{\left\lbrack {{J_{\exp}\left( t_{i} \right)} - {J_{model}\left( t_{i} \right)}} \right\rbrack^{2}}{\left\lbrack {J_{\exp}\left( t_{i} \right)} \right\rbrack^{2}}.}}$

For reliable conversion of the time-dependent creep data into thefrequency-dependent dynamic data, the frequency range needs to belimited by the testing time of the creep measurement. If it is possibleto obtain precise experimental data over the entire range of creep timeuntil the creep compliance reaches the steady state, the exact functionof retardation spectra over the entire range of time scale also can becalculated. However, it is often not practical to obtain such data forhigh molecular weight polymers, which have very long relaxation times.The creep data only contain information within a limited range of time,so that the frequency range is limited by the duration time t_(N) of thecreep test, i.e., valid information for frequencies is in the range ofω>t_(N) ⁻¹, and the extrapolated data outside this frequency range canbe influenced by artifacts of the fittings.

For the rheological measurements involving a creep adjustment, thepolymer samples were compression molded at 182° C. for a total of 3 min.The samples were allowed to melt at a relatively low pressure for 1 minand then subjected to a high molding pressure for an additional 2 min.The molded samples were then quenched in a room temperature press, andthen 25.4 mm diameter disks were stamped out of the molded slabs for themeasurement in the rotational rheometer. The measurements were performedin parallel plates of 25 mm diameter at 190° C. using acontrolled-stress rheometer equipped with an air bearing system (PhysicaMCR-500, Anton Paar). The test chamber of the rheometer was purged withnitrogen to minimize oxidative degradation. After thermal equilibration,the specimens were squeezed between the plates to a 1.6 mm thickness,and the excess was trimmed. A total of 8 min elapsed between the timethe sample was inserted and the time the test was started. For thedynamic frequency sweep measurement, small-strain (1˜10%) oscillatoryshear in the linear viscoelastic regime was applied at angularfrequencies from 0.0316 to 316 sec⁻¹. The creep test was performed for10,200 sec (170 min) to limit the overall testing time within 4 hr,since sample throughput and thermal stability were concerns. Byconverting the time dependent creep data to frequency dependent dynamicdata, the low frequency range was extended down to 10⁻⁴ rad/sec, twoorders of magnitude lower than the frequency range of the dynamic test.The complex viscosity (|η8|) versus frequency (ω) data were curve fittedusing the Carreau-Yasuda model.

One of the major concerns in performing the creep test, and indeed anylong time scale measurement, was that the sample does not appreciablychange during the measurement, which may take several hours to perform.If a polymer sample is heated for long time period without properthermal stabilization (e.g., antioxidants), changes in the polymer canoccur that can have a significant effect on the rheological behavior ofthe polymer and its characterization. Polymers which are being testedshould have thermal stability for at least 4-5 hr at 190° C. undernitrogen; for example, ethylene polymers containing at least 0.4 wt. %of antioxidants were found to be stable enough to obtain valid creepadjustment data.

For the rheological measurement in the parallel plates, the specimen wassqueezed between the plates to a 1.6 mm thickness, and then the excesswas trimmed. When the sample was trimmed with large forces on onedirection, some residual stress was generated to cause the strain todrift. Therefore, performing the creep test right after sample trimmingshould be avoided, because the residual stress can affect the subsequentcreep measurement, particularly for the highly viscoelastic resinshaving long relaxation times. If the applied stress of the creep test isnot large enough, the resulting strain can be so small that the creepresults can be influenced by the artifact of the strain drifting. Inorder to minimize this effect, samples were trimmed as gently aspossible, and the creep test was conducted after 2000 sec of waitingtime, in order to allow relaxation of any residual stress.

The appropriate magnitude of applied stress σ₀ is important for reliablecreep data. The stress σ₀ must be sufficiently small such that thestrain will stay within the linear viscoelastic regime, and it must besufficiently large such that the strain signal is strong enough toprovide satisfactory resolution of data for good precision. Although notlimited thereto, a suitable applied stress was equal to the complexmodulus |G*| at a frequency of 0.01 rad/sec multiplied by 0.04.

The long chain branches (LCB) per 1000 total carbon atoms can becalculated using the method of Janzen and Colby (J. Mol. Struct.,485/486, 569-584 (1999)), from values of zero shear viscosity, η₀(determined from the Carreau-Yasuda model, described hereinabove), andmeasured values of Mw obtained using a Dawn EOS multiangle lightscattering detector (Wyatt). See also U.S. Pat. No. 8,114,946; J. Phys.Chem. 1980, 84, 649; and Y. Yu, D. C. Rohlfing, G. R Hawley, and P. J.DesLauriers, Polymer Preprints, 44, 49-50 (2003). These references areincorporated herein by reference in their entirety.

Short chain branch (SCB) content and short chain branching distribution(SCBD) across the molecular weight distribution were determined via anIR5-detected GPC system (IR5-GPC), wherein the GPC system was a PL220GPC/SEC system (Polymer Labs, an Agilent company) equipped with threeStyragel HMW-6E columns (Waters, MA) for polymer separation. Athermoelectric-cooled IR5 MCT detector (IR5) (Polymer Char, Spain) wasconnected to the GPC columns via a hot-transfer line. Chromatographicdata were obtained from two output ports of the IR5 detector. First, theanalog signal went from the analog output port to a digitizer beforeconnecting to Computer “A” for molecular weight determinations via theCirrus software (Polymer Labs, now an Agilent Company) and the integralcalibration method using a broad MWD HDPE Marlex™ BHB5003 resin (ChevronPhillips Chemical) as the broad molecular weight standard. The digitalsignals, on the other hand, went via a USB cable directly to Computer“B” where they were collected by a LabView data collection softwareprovided by Polymer Char. Chromatographic conditions were set asfollows: column oven temperature of 145° C.; flowrate of 1 mL/min;injection volume of 0.4 mL; and polymer concentration of about 2 mg/mL,depending on sample molecular weight. The temperatures for both thehot-transfer line and IR5 detector sample cell were set at 150° C.,while the temperature of the electronics of the IR5 detector was set at60° C. Short chain branching content was determined via an in-housemethod using the intensity ratio of CH₃ (I_(CH3)) to CH₂ (I_(CH2))coupled with a calibration curve. The calibration curve was a plot ofSCB content (x_(SCH)) as a function of the intensity ratio ofI_(CH3)/I_(CH2). To obtain a calibration curve, a group of polyethyleneresins (no less than 5) of SCB level ranging from zero to ca. 32SCB/1,000 total carbons (SCB Standards) were used. All these SCBStandards had known SCB levels and flat SCBD profiles pre-determinedseparately by NMR and the solvent-gradient fractionation coupled withNMR (SGF-NMR) methods. Using SCB calibration curves thus established,profiles of short chain branching distribution across the molecularweight distribution were obtained for resins fractionated by the IR5-GPCsystem under exactly the same chromatographic conditions as for theseSCB standards. A relationship between the intensity ratio and theelution volume was converted into SCB distribution as a function of MWDusing a predetermined SCB calibration curve (i.e., intensity ratio ofI_(CH3)/I_(CH2) vs. SCB content) and MW calibration curve (i.e.,molecular weight vs. elution time) to convert the intensity ratio ofI_(CH3)/I_(CH2) and the elution time into SCB content and the molecularweight, respectively.

Blow molded 1-gallon containers were produced under suitable conditionson a Uniloy reciprocating blow molding machine. The parison was extrudedusing a 2.5″ diverging die and then blown into a mold to produce the1-gallon containers weighing approximately 105 g.

Fluorided silica-coated aluminas used in Examples 2-7 were prepared asfollows. Alumina A, from W.R. Grace Company, was first calcined in dryair at about 600° C. for approximately 6 hours, cooled to ambienttemperature, and then contacted with tetraethylorthosilicate inisopropanol to equal 25 wt. % SiO₂. After drying, the silica-coatedalumina was calcined at 600° C. for 3 hours. Fluorided silica-coatedalumina (7 wt. % F) was prepared by impregnating the calcinedsilica-coated alumina with an ammonium bifluoride solution in methanol,drying, and then calcining for 3 hours at 600° C. in dry air. Afterward,the fluorided silica-coated alumina was collected and stored under drynitrogen, and was used without exposure to the atmosphere.

Pilot plant polymerizations were conducted in a 30-gallon slurry loopreactor at a production rate of approximately 30 pounds of polymer perhour. Polymerization runs were carried out under continuous particleform process conditions in a loop reactor (also referred to as a slurryprocess) by contacting separate metallocene solutions, an organoaluminumsolution (triisobutylaluminum, TIBA), and an activator-support(fluorided silica-coated alumina) in a 1 L stirred autoclave (30 minresidence time) with output to the loop reactor.

Ethylene used was polymerization grade ethylene which was purifiedthrough a column of AZ 300 (activated at 300-500° F. in nitrogen).1-Hexene was polymerization grade 1-hexene (obtained from ChevronPhillips Chemical Company) which was purified by nitrogen purging andstorage over AZ 300 activated at 300-500° F. in nitrogen. Liquidisobutane was used as the diluent.

Certain polymerization conditions for Examples 2-7 are provided in thetable below (mole % ethylene and ppm by weight of triisobutylaluminum(TIBA) are based on isobutane diluent). The polymerization conditionsalso included a reactor pressure of 590 psig, a polymerizationtemperature of 90° C., a feed rate of 33.1 lb/hr ethylene, and 2.8-3.2ppm total of MET 1 and MET 2 (based on the weight of isobutane diluent).The structures for MET 1 and MET 2, used in Examples 2-7, are shownbelow:

1-Hexene H₂ Weight ratio C₂H₄ TIBA Example (lb/hr) (lb/hr) MET 1/MET 2mole % ppm 2 0.24 0.0035 0.85 12.33 85.4 3 0.20 0.0038 0.81 11.33 106.54 0.21 0.0037 0.83 11.76 84.8 5 0.20 0.0037 0.78 12.43 112.8 6 0.210.0037 0.79 12.04 113.0 7 0.13 0.0037 0.77 12.25 130.4

Examples 1-7

Example 1 was a broad monomodal HDPE resin, having a nominal 0.35 MI and0.955 density, produced using a chromium-based catalyst system(Chevron-Phillips Chemical Company LP). Table I and Table II summarizethe molecular weight, melt index, density, and ESCR (100% igepal)characteristics of Examples 1-7, and FIG. 1 illustrates the bimodalmolecular weight distributions (amount of polymer versus the logarithmof molecular weight) of the polymers of Examples 2-7 versus that ofExample 1. The polymers of Examples 2-7 had Mz values ranging from about1,500,000 to 2,000,000 g/mol, Mw values ranging from about 180,000 toabout 270,000 g/mol, Mn values ranging from about 20,000 to about 24,000g/mol, Mw/Mn values ranging from about 8.5 to about 12, and Mz/Mw valuesranging from about 7 to about 9. In contrast, the polymer of Example 1had lower Mz, Mw, Mn, Mw/Mn, and Mz/Mw values. The polymers of Examples2-7 had densities ranging from about 0.96 to 0.961 g/cm³ and MI'sranging from about 0.2 to 1 g/10 min; the polymer of Example 1 had asimilar melt index but a significantly lower density (0.955).Unexpectedly, however, the ESCR (100% igepal) properties of Examples 2-7were far superior to those of Example 1; for instance, the ESCRperformance of Examples 3-7 was at least 50 times better. Hence, thepolymers described herein can provide improved ESCR at an equivalent (orhigher) density and/or MI, as compared to chromium-based resins.

Drop impact testing was performed on 1-gallon containers that were blowmolded from the polymers of Examples 1-7, generally in accordance withASTM D2463. Blow molded containers produced from the polymer of Example1 passed the drop impact test at a height of 12.5 ft. Surprisingly, evenwith a significantly higher density, blow molded containers producedfrom the polymers of Examples 2 and 7 also passed the drop impact testat a height of 12.5 ft. Additionally, blow molded containers producedfrom the polymers of Examples 3, 4, and 6 were almost as impactresistant, surviving the drop impact test at a height of 11.5 ft. Blowmolded containers produced from the polymer of Example 5 passed the dropimpact test at a height of 10.3 ft.

As shown in FIGS. 2-3, certain polymers described herein had a reversecomonomer distribution (e.g., relatively more short chain branches (SCB)at the higher molecular weights; assumes 2 methyl chain ends (CE)), ascontrasted with the standard comonomer distribution expected from achromium-based catalyst system. For instance, in FIGS. 2-3, the numberof SCB per 1000 total carbon (TC) atoms of the polymer at Mw (or Mz) isgreater than at Mn for the polymers of Examples 2 and 7.

FIGS. 4-5 illustrate the rheological properties at 190° C. for thepolymers of Examples 1-7 (and 7A-7D), and Table III and Table IVsummarize certain rheological characteristics of the these polymers.Surprisingly, FIG. 4 demonstrates that metallocene-based polymers(Examples 2-7) were produced having roughly equivalent processability tothat of a chromium-based polymer (Example 1).

The polymer resin of Example 7A was prepared by first dry blending thepolymer base resin of Example 7 with 1000 ppm by weight (ppmw) of amasterbatch containing a polyethylene carrier resin and2,5-dimethyl-2,5-di(t-butylperoxy)hexane. Based on the weight percent ofthe two 0-0 groups in the compound and the loading in concentrate, the1000 ppmw loading of the masterbatch in the base resin equated to about50 ppmw of peroxide groups, based on the weight of the base resin. Theblend of the base resin and peroxide masterbatch was compounded using atwin screw extrusion system, and then pelletized to form theethylene/1-hexene copolymer of Example 7A. Compounding was done on alaboratory ZSK-30 twin screw extruder using nitrogen purge at theextruder feed port. A 2-hole strand die plate was used for pelletizing.Melt temperature was about 485° F. The polymers of Examples 7B, 7C, and7D were prepared as described for Example 7A, except that the peroxideconcentrate loading was 2000 ppmw, 3000 ppmw, and 4000 ppmw,respectively (100 ppmw, 150 ppmw, and 200 ppmw, respectively, ofperoxide groups based on the weight of the base resin).

Table III and FIG. 5 demonstrate that the addition of peroxide generallyincreased the zero-shear viscosity and relaxation time, but decreasedthe CY-a parameter. Peroxide addition also decreased the ESCR, but theperformance of the polymers of Examples 7A-7D was, unexpectedly, stillfar superior to that of Example 1. Hence, melt strength, which can beimportant in blow molding and other applications, can be increased withthe addition of peroxide, while still maintaining acceptable ESCRperformance.

As described herein, Applicants determined that the die swell of anethylene polymer correlates with the rheological slope parameter, i.e.,the slope of a plot of the viscosity (Pa-sec) versus shear rate (sec⁻¹)at 100 sec⁻¹ for the ethylene polymer at 190° C. Generally, the higherthe rheological slope parameter, the higher the die swell. Table IVdemonstrates that the polymers of Examples 7 and 7A-7D had rheologicalslope parameters that were comparable to that of Example 1, and thuswould be expected to have comparable die swell during processing, e.g.,blow molding. Peroxide addition typically decreased the rheologicalslope parameter. The polymers of Examples 2-6 had rheological slopeparameters in the 0.45-0.57 range. The rheological parameters in TableIII and Table IV were determined at 190° C. using the Carreau-Yasuda(CY) empirical model with creep adjustment, as described herein, withthe exception of Example 1, where the parameters were determined withoutcreep adjustment.

Table V summarizes the properties of the lower molecular weight (LMW)component and the higher molecular weight (HMW) component of thepolymers of Examples 2-7. The respective LMW and HMW componentproperties were determined by deconvoluting the molecular weightdistribution (see e.g., FIG. 1) of each polymer. The relative amounts ofthe LMW and HMW components (weight percentages) in the polymer, and Mpof the LMW component and Mp of the HMW component, were determined usinga commercial software program (Systat Software, Inc., Peak Fit™ v.4.05). The other molecular weight parameters for the LMW and HMWcomponents (e.g., Mn, Mw, Mz, etc., of each component) were determinedby using the deconvoluted data from the Peak Fit™ program, and applyinga Schulz-Flory distribution mathematical function and a Gaussian peakfit, as generally described in U.S. Pat. No. 7,300,983, which isincorporated herein by reference in its entirety. The wt. % of thehigher molecular weight component ranged from about 9 to 16 wt. %, Mp ofthe higher molecular weight component range from about 700,000 to about1,000,000 g/mol, and Mp of the lower molecular weight component rangedfrom about 55,000 to about 61,000 g/mol.

TABLE I Examples 1-7 - Molecular Weight Characterization Example Mn MwMz Number (kg/mol) (kg/mol) (kg/mol) Mw/Mn Mz/Mw 1 18.4 152 1042 8.3 6.82 20.8 186 1567 8.9 8.4 3 22.0 198 1626 9.0 8.2 4 22.4 189 1594 8.5 8.45 22.8 242 1854 10.6 7.6 6 22.8 223 1736 9.8 7.8 7 22.0 267 1986 12.07.4

TABLE II Examples 1-7 - MI, HLMI, Density, and ESCR (100%)Characteristics Example MI HLMI Density ESCR - B Number (g/10 min) (g/10min) HLMI/MI (g/cc) (100%, hr) 1 0.35 35 100 0.955 35 2 1.04 64 620.9600 409 3 0.62 62 100 0.9608 >2000 4 0.82 75 91 0.9607 >2000 5 0.3438 112 0.9600 >2000 6 0.42 44 105 0.9601 >2000 7 0.23 29 126 0.9603>2000

TABLE III Examples 1-7 - ESCR (10%) and Rheological Properties at 190°C. Zero Relax- Rheological ESCR Shear ation Breadth Peroxide Condi-Example Viscosity Time CY-a Amount tion B Number (Pa-sec) (sec)Parameter (ppm) (10%, hr) 1 1.37E+06 2.47E+00 0.1279 0 2 4.92E+05 0 34.20E+05 0 4 3.73E+05 0 5 7.13E+05 0 6 5.84E+05 0 7 8.03E+05 1.52E+010.2437 0 414   7A 3.76E+06 4.98E+01 0.1681 50 424   7B 5.19E+07 6.29E+020.1209 100 266   7C 5.38E+09 5.86E+04 0.0813 150 227   7D 9.85E+117.61E+06 0.0584 200 223

TABLE IV Examples 1 and 7 - Rheological Slope Parameters at 190° C.Example Rheological Slope Number Parameter @ 100 sec⁻¹ 1   0.4455 7  0.4659 7A 0.4592 7B 0.4509 7C 0.4456 7D 0.4428

TABLE V Lower Molecular Weight and Higher Molecular Weight ComponentProperties of Examples 2-7 (kg/mol) Lower Molecular Component PropertiesHigher Molecular Weight Component Properties Example % Mn Mw Mz Mp Mw/MnMz/Mw % Mn Mw Mz Mp Mw/Mn Mz/Mw 2 91 19.0 69.1 136 58.9 3.6 2.0 9 5541110 1907 851 2.0 1.7 3 90 16.8 65.2 128 56.2 3.9 2.0 10 571 1089 1819871 1.9 1.7 4 89 16.4 61.9 118 55.0 3.8 1.9 11 340 879 1597 741 2.6 1.85 84 15.7 63.7 121 57.5 4.1 1.9 16 243 978 1814 891 4.0 1.9 6 86 15.863.8 123 55.0 4.0 1.9 14 321 1005 1809 891 3.1 1.8 7 84 17.2 66.3 12960.3 3.8 1.9 16 362 1107 2038 955 3.0 1.8

The invention is described above with reference to numerous aspects andembodiments, and specific examples. Many variations will suggestthemselves to those skilled in the art in light of the above detaileddescription. All such obvious variations are within the full intendedscope of the appended claims. Other embodiments of the invention caninclude, but are not limited to, the following (embodiments aredescribed as “comprising” but, alternatively, can “consist essentiallyof” or “consist of”):

Embodiment 1. An ethylene polymer comprising a higher molecular weightcomponent and a lower molecular weight component, wherein the ethylenepolymer has a density of greater than or equal to about 0.945 g/cm³, amelt index (MI) of less than or equal to about 1.5 g/10 min, a ratio ofhigh load melt index to melt index (HLMI/MI) in a range from about 40 toabout 175, and a slope of a plot of the viscosity (Pa-sec) versus shearrate (sec⁻¹) of the ethylene polymer at 100 sec⁻¹ in a range from about0.42 to about 0.65.

Embodiment 2. An ethylene polymer comprising a higher molecular weightcomponent and a lower molecular weight component, wherein the ethylenepolymer has a density of greater than or equal to about 0.945 g/cm³, amelt index (MI) of less than or equal to about 1.5 g/10 min, a ratio ofhigh load melt index to melt index (HLMI/MI) in a range from about 40 toabout 175, a peak molecular weight (Mp) of the higher molecular weightcomponent in a range from about 650,000 to about 1,100,000 g/mol, a Mpof the lower molecular weight component in a range from about 40,000 toabout 80,000 g/mol, and a ratio of Mw/Mn in a range from about 5 toabout 18.

Embodiment 3. The polymer defined in embodiment 1 or 2, wherein theethylene polymer has an environmental stress crack resistance (ESCR,100% igepal) in any range disclosed herein, e.g., at least 400 hours, atleast 600 hours, at least 1,000 hours, at least 1,500 hours, at least2,000 hours, etc., and/or the ethylene polymer has an environmentalstress crack resistance (ESCR, 10% igepal) in any range disclosedherein, e.g., at least 100 hours, at least 150 hours, at least 200hours, at least 250 hours, at least 400 hours, etc.

Embodiment 4. The polymer defined in any one of embodiments 1-3, whereinthe ethylene polymer has a MI in any range disclosed herein, e.g., from0 to about 1, from about 0.05 to about 1.2, from about 0.1 to about 0.9,from about 0.2 to about 0.9, from about 0.2 to about 0.8 g/10 min, etc.

Embodiment 5. The polymer defined in any one of embodiments 1-4, whereinthe ethylene polymer has a ratio of HLMI/MI in any range disclosedherein, e.g., from about 50 to about 175, from about 50 to about 150,from about 60 to about 160, from about 45 to about 145, from about 50 toabout 130, etc.

Embodiment 6. The polymer defined in any one of embodiments 1-5, whereinthe ethylene polymer has a density in any range disclosed herein, e.g.,greater than or equal to about 0.95, greater than or equal to about0.955, from about 0.945 to about 0.965, from about 0.95 to about 0.965,from about 0.95 to about 0.962, from about 0.955 to about 0.965, fromabout 0.957 to about 0.963 g/cm³, etc.

Embodiment 7. The polymer defined in any one of embodiments 1-6, whereinthe ethylene polymer has a slope of a plot of the viscosity (Pa-sec)versus shear rate (sec⁻¹) of the ethylene polymer at 100 sec⁻¹ (and 190°C.) in any range disclosed herein, e.g., from about 0.42 to about 0.6,from about 0.42 to about 0.55, from about 0.44 to about 0.65, from about0.44 to about 0.55, from about 0.45 to about 0.6, etc.

Embodiment 8. The polymer defined in any one of embodiments 1-7, whereinthe higher molecular weight component has a Mp in any range disclosedherein, e.g., from about 700,000 to about 1,100,000, from about 650,000to about 1,000,000, from about 700,000 to about 1,000,000, from about725,000 to about 975,000 g/mol, etc.

Embodiment 9. The polymer defined in any one of embodiments 1-8, whereinthe lower molecular weight component has a Mp in any range disclosedherein, e.g., from about 40,000 to about 75,000, from about 45,000 toabout 80,000, from about 45,000 to about 75,000, from about 45,000 toabout 70,000 g/mol, etc.

Embodiment 10. The polymer defined in any one of embodiments 1-9,wherein the higher molecular weight component has a weight-averagemolecular weight (Mw) in any range disclosed herein, e.g., from about825,000 to about 1,500,000, from about 825,000 to about 1,300,000, fromabout 850,000 to about 1,350,000, from about 850,000 to about 1,250,000g/mol, etc.

Embodiment 11. The polymer defined in any one of embodiments 1-10,wherein the lower molecular weight component has a weight-averagemolecular weight (Mw) in any range disclosed herein, e.g., from about45,000 to about 85,000, from about 45,000 to about 80,000, from about50,000 to about 80,000, from about 55,000 to about 80,000 g/mol, etc.

Embodiment 12. The polymer defined in any one of embodiments 1-11,wherein the higher molecular weight component has a number-averagemolecular weight (Mn) in any range disclosed herein, e.g., from about175,000 to about 700,000, from about 175,000 to about 600,000, fromabout 200,000 to about 650,000, from about 200,000 to about 600,000g/mol, etc.

Embodiment 13. The polymer defined in any one of embodiments 1-12,wherein the lower molecular weight component has a number-averagemolecular weight (Mn) in any range disclosed herein, e.g., from about8,000 to about 35,000, from about 10,000 to about 35,000, from about10,000 to about 30,000, from about 12,000 to about 25,000 g/mol, etc.

Embodiment 14. The polymer defined in any one of embodiments 1-13,wherein the ethylene polymer has a Mw in any range disclosed herein,e.g., from about 150,000 to about 375,000, from about 150,000 to about350,000, from about 150,000 to about 300,000, from about 175,000 toabout 375,000, from about 175,000 to about 350,000, from about 175,000to about 300,000 g/mol, etc.

Embodiment 15. The polymer defined in any one of embodiments 1-14,wherein the ethylene polymer has a Mn in any range disclosed herein,e.g., from about 10,000 to about 40,000, from about 12,000 to about35,000, from about 12,000 to about 30,000, from about 15,000 to about40,000, from about 15,000 to about 35,000 g/mol, etc.

Embodiment 16. The polymer defined in any one of embodiments 1-15,wherein the ethylene polymer has a z-average molecular weight (Mz) inany range disclosed herein, e.g., from about 800,000 to about 4,000,000,from about 900,000 to about 3,500,000, from about 1,000,000 to about4,000,000, from about 1,000,000 to about 3,000,000, from about 900,000to about 2,500,000 g/mol, etc.

Embodiment 17. The polymer defined in any one of embodiments 1-16,wherein the ethylene polymer has a ratio of Mw/Mn in any range disclosedherein, e.g., from about 5 to about 18, from about 5 to about 15, fromabout 6 to about 18, from about 6 to about 15, from about 7 to about 18,from about 7 to about 15, from about 8 to about 14, etc.

Embodiment 18. The polymer defined in any one of embodiments 1-17,wherein the ethylene polymer has a ratio of Mz/Mw in any range disclosedherein, e.g., from about 5 to about 12, from about 5.5 to about 11, fromabout 6 to about 10, from about 6.5 to about 9.5, etc.

Embodiment 19. The polymer defined in any one of embodiments 1-18,wherein the higher molecular weight component has a ratio of Mz/Mw inany range disclosed herein, e.g., less than or equal to about 2.5, lessthan or equal to about 2.2, from about 1.5 to about 2.5, from about 1.5to about 2.2, etc.

Embodiment 20. The polymer defined in any one of embodiments 1-19,wherein the lower molecular weight component has a ratio of Mz/Mw in anyrange disclosed herein, e.g., less than or equal to about 2.8, less thanor equal to about 2.5, from about 1.5 to about 2.8, from about 1.6 toabout 2.5, from about 1.6 to about 2.4, etc.

Embodiment 21. The polymer defined in any one of embodiments 1-20,wherein an amount of the higher molecular weight component, based on thetotal polymer, is in any range of weight percentages disclosed herein,e.g., less than or equal to about 35%, less than or equal to about 30%,less than or equal to about 25%, less than or equal to about 22%, lessthan or equal to about 20%, from about 5 to about 30%, from about 4 toabout 25%, from about 5 to about 22%, from about 5 to about 20%, fromabout 6 to about 25%, from about 6 to about 22%, etc.

Embodiment 22. The polymer defined in any one of embodiments 1-21,wherein the ethylene polymer has a HLMI in any range disclosed herein,e.g., from about 15 to about 100, from about 20 to about 90, from about20 to about 85, from about 35 to about 100, from about 15 to about 75,from about 30 to about 80 g/10 min, etc.

Embodiment 23. The polymer defined in any one of embodiments 1-22,wherein the ethylene polymer has less than about 0.008 long chainbranches (LCB) per 1000 total carbon atoms, e.g., less than about 0.005LCB, less than about 0.003 LCB, etc.

Embodiment 24. The polymer defined in any one of embodiments 1-23,wherein the ethylene polymer has a non-conventional (flat or reverse)comonomer distribution, e.g., the number of short chain branches (SCB)per 1000 total carbon atoms of the polymer at Mw is greater than orequal to the number at Mn, the number of short chain branches (SCB) per1000 total carbon atoms of the polymer at Mz is greater than or equal tothe number at Mw, the number of SCB per 1000 total carbon atoms of thepolymer at Mz is greater than or equal to the number at Mn, the numberof short chain branches (SCB) per 1000 total carbon atoms of the polymerat a molecular weight of 10⁶ is greater than or equal to the number at amolecular weight of 10⁵, etc.

Embodiment 25. The polymer defined in any one of embodiments 1-24,wherein the ethylene polymer has a CY-a parameter in any range disclosedherein, e.g., from about 0.02 to about 0.3, from about 0.04 to about0.2, from about 0.04 to about 0.18, etc.

Embodiment 26. The polymer defined in any one of embodiments 1-25,wherein the ethylene polymer has a zero-shear viscosity (using theCarreau-Yasuda model with creep adjustment) in any range disclosedherein, e.g., greater than or equal to about 1×10⁵, greater than orequal to about 2×10⁵, in a range from about 1×10⁵ to about 1×10⁷, in arange from about 2×10⁵ to about 1×10⁷ Pa-sec, etc.

Embodiment 27. The polymer defined in any one of embodiments 1-26,wherein the ethylene polymer has a zero-shear viscosity (using theCarreau-Yasuda model with creep adjustment) in any range disclosedherein, e.g., greater than or equal to about 1×10⁶, greater than orequal to about 2×10⁶, in a range from about 1×10⁶ to about 1×10¹⁴, in arange from about 2×10⁶ to about 1×10¹² Pa-sec, etc.

Embodiment 28. The polymer defined in any one of embodiments 1-27,wherein the ethylene polymer has a bimodal molecular weightdistribution.

Embodiment 29. The polymer defined in any one of embodiments 1-28,wherein the ethylene polymer is a single reactor product, e.g., not apost-reactor blend of two polymers, for instance, having differentmolecular weight characteristics.

Embodiment 30. The polymer defined in any one of embodiments 1-29,wherein the ethylene polymer is an ethylene/α-olefin copolymer.

Embodiment 31. The polymer defined in any one of embodiments 1-30,wherein the ethylene polymer is an ethylene/1-butene copolymer, anethylene/1-hexene copolymer, or an ethylene/1-octene copolymer.

Embodiment 32. The polymer defined in any one of embodiments 1-31,wherein the ethylene polymer is an ethylene/1-hexene copolymer.

Embodiment 33. The polymer defined in any one of embodiments 1-32,wherein the ethylene polymer is produced by a process comprisingcontacting a base resin with a peroxide compound at a temperaturesufficient to generate peroxide groups at 10-400 ppm of peroxide groupsbased on the weight of the base resin.

Embodiment 34. The polymer defined in embodiment 33, wherein the step ofcontacting the base resin with the peroxide compound comprises meltprocessing a blend (or mixture) of the base resin and the peroxidecompound at any melt processing temperature disclosed herein, e.g., in arange from about 120 to about 300° C., in a range from about 150 toabout 250° C., in a range from about 175 to about 225° C., etc.

Embodiment 35. The polymer defined in embodiment 34, wherein the meltprocessing is performed in a twin screw extrusion system.

Embodiment 36. The polymer defined in embodiment 34, wherein the meltprocessing is performed in a single screw extrusion system.

Embodiment 37. The polymer defined in any one of embodiments 33-36,wherein the base resin is an ethylene polymer having the polymercharacteristics defined in any one of embodiments 1-32.

Embodiment 38. The polymer defined in any one of embodiments 1-37,wherein the base resin and/or the ethylene polymer is/are produced usinga Ziegler-Natta catalyst system.

Embodiment 39. The polymer defined in any one of embodiments 1-37,wherein the base resin and/or the ethylene polymer is/are produced usinga metallocene-based catalyst system.

Embodiment 40. The polymer defined in embodiment 39, wherein themetallocene-based catalyst system comprises catalyst component Icomprising any unbridged metallocene compound disclosed herein, catalystcomponent II comprising any bridged metallocene compound disclosedherein, any activator disclosed herein, and optionally, any co-catalystdisclosed herein.

Embodiment 41. The polymer defined in embodiment 40, wherein catalystcomponent I comprises an unbridged zirconium or hafnium basedmetallocene compound containing two cyclopentadienyl groups, two indenylgroups, or a cyclopentadienyl and an indenyl group.

Embodiment 42. The polymer defined in embodiment 40, wherein catalystcomponent I comprises an unbridged metallocene compound having formula(I):

wherein M is any Group IV transition metal disclosed herein, Cp^(A) andCp^(B) independently are any cyclopentadienyl or indenyl group disclosedherein, and each X independently is any monoanionic ligand disclosedherein.

Embodiment 43. The polymer defined in any one of embodiments 40-42,wherein catalyst component II comprises a bridged zirconium or hafniumbased metallocene compound with a cyclopentadienyl group and a fluorenylgroup, and with an alkenyl substituent on the bridging group and/or onthe cyclopentadienyl group.

Embodiment 44. The polymer defined in any one of embodiments 40-42,wherein catalyst component II comprises a bridged metallocene compoundhaving formula (II):

wherein M is any Group IV transition metal disclosed herein, Cp is anycyclopentadienyl, indenyl, or fluorenyl group disclosed herein, each Xindependently is any monoanionic ligand disclosed herein, R^(X) andR^(Y) independently are any substituent disclosed herein, and E is anybridging group disclosed herein.

Embodiment 45. The polymer defined in any one of embodiments 40-44,wherein the activator comprises an activator-support, an aluminoxanecompound, an organoboron or organoborate compound, an ionizing ioniccompound, or any combination thereof.

Embodiment 46. The polymer defined in any one of embodiments 40-45,wherein the activator comprises an aluminoxane compound.

Embodiment 47. The polymer defined in any one of embodiments 40-45,wherein the activator comprises an activator-support, theactivator-support comprising any solid oxide treated with anyelectron-withdrawing anion disclosed herein.

Embodiment 48. The polymer defined in embodiment 47, wherein theactivator-support comprises fluorided alumina, chlorided alumina,bromided alumina, sulfated alumina, fluorided silica-alumina, chloridedsilica-alumina, bromided silica-alumina, sulfated silica-alumina,fluorided silica-zirconia, chlorided silica-zirconia, bromidedsilica-zirconia, sulfated silica-zirconia, fluorided silica-titania,fluorided silica-coated alumina, sulfated silica-coated alumina,phosphated silica-coated alumina, or any combination thereof.

Embodiment 49. The polymer defined in embodiment 47, wherein theactivator-support comprises a fluorided solid oxide and/or a sulfatedsolid oxide.

Embodiment 50. The polymer defined in any one of embodiments 40-49,wherein the metallocene-based catalyst system comprises a co-catalyst,e.g., any co-catalyst disclosed herein.

Embodiment 51. The polymer defined in embodiment 50, wherein theco-catalyst comprises any organoaluminum compound disclosed herein,e.g., trimethylaluminum, triethylaluminum, triisobutylaluminum, etc.

Embodiment 52. The polymer defined in any one of embodiments 40-51,wherein a weight ratio of catalyst component I to catalyst component IIin the catalyst system is in any range disclosed herein, e.g., fromabout 10:1 to about 1:10, from about 5:1 to about 1:5, from about 2:1 toabout 1:2, etc.

Embodiment 53. The polymer defined in any one of embodiments 1-52,wherein the base resin and/or the ethylene polymer is/are produced inany polymerization reactor system and under any polymerizationconditions disclosed herein.

Embodiment 54. The polymer defined in embodiment 53, wherein thepolymerization reactor system comprises a batch reactor, a slurryreactor, a gas-phase reactor, a solution reactor, a high pressurereactor, a tubular reactor, an autoclave reactor, or a combinationthereof.

Embodiment 55. The polymer defined in embodiment 53, wherein thepolymerization reactor system comprises a slurry reactor, a gas-phasereactor, a solution reactor, or a combination thereof.

Embodiment 56. The polymer defined in embodiment 53, wherein thepolymerization reactor system comprises a loop slurry reactor.

Embodiment 57. The polymer defined in any one of embodiments 53-56,wherein the polymerization reactor system comprises a single reactor, 2reactors, or more than 2 reactors.

Embodiment 58. The polymer defined in any one of embodiments 53-57,wherein the polymerization conditions comprise a polymerization reactiontemperature in a range from about 60° C. to about 120° C. and a reactionpressure in a range from about 200 to about 1000 psig (about 1.4 toabout 6.9 MPa).

Embodiment 59. The polymer defined in any one of embodiments 53-58,wherein the polymerization conditions are substantially constant, e.g.,for a particular polymer grade.

Embodiment 60. The polymer defined in any one of embodiments 53-59,wherein hydrogen is added to the polymerization reactor system.

Embodiment 61. An article of manufacture (e.g., a blow molded article)comprising the ethylene polymer (or base resin) defined in any one ofembodiments 1-60.

Embodiment 62. An article comprising the ethylene polymer (or baseresin) defined in any one of embodiments 1-60, wherein the article is anagricultural film, an automobile part, a bottle, a drum, a fiber orfabric, a food packaging film or container, a food service article, afuel tank, a geomembrane, a household container, a liner, a moldedproduct, a medical device or material, a pipe, a sheet or tape, or atoy.

1. An ethylene polymer comprising a higher molecular weight componentand a lower molecular weight component, wherein the ethylene polymer hasa density of greater than or equal to about 0.95 g/cm³, a melt index(MI) of less than or equal to about 1.5 g/10 min, a ratio of high loadmelt index to melt index (HLMI/MI) in a range from about 40 to about175, a bimodal molecular weight distribution, less than about 0.008 longchain branches per 1000 total carbon atoms, a non-conventional comonomerdistribution, and a slope of a plot of the viscosity (Pa-sec) versusshear rate (sec⁻¹) at 190° C. of the ethylene polymer at 100 sec⁻¹ in arange from about 0.42 to about 0.65.
 2. The polymer of claim 1, whereinthe ethylene polymer has: a density in a range from about 0.95 to about0.965 g/cm³; a HLMI in a range from about 15 to about 100 g/10 min; anESCR (100% igepal) of at least 1000 hours; and an ESCR (10% igepal) ofat least 200 hours.
 3. (canceled)
 4. The polymer of claim 1, wherein theethylene polymer has: a ratio of Mw/Mn in a range from about 6 to about18; a ratio of Mz/Mw in a range from about 6 to about 10; a Mw in arange from about 150,000 to about 375,000 g/mol; a Mn in a range fromabout 12,000 to about 35,000 g/mol; or a Mz in a range from about1,000,000 to about 3,000,000 g/mol; or any combination thereof.
 5. Thepolymer of claim 1, wherein the ethylene polymer has: a melt index in arange from about 0.1 to about 1 g/10 min; a ratio of HLMI/MI in a rangefrom about 60 to about 160; and a density in a range from about 0.955 toabout 0.965 g/cm³.
 6. The polymer of claim 5, wherein the ethylenepolymer is an ethylene/α-olefin copolymer.
 7. The polymer of claim 1,wherein the ethylene polymer has: a CY-a parameter at 190° C. in a rangefrom about 0.02 to about 0.3; and the slope of the plot of the viscosity(Pa-sec) versus shear rate (sec⁻¹) at 190° C. of the ethylene polymer at100 sec⁻¹ in a range from about 0.44 to about 0.5.
 8. The polymer ofclaim 1, wherein the ethylene polymer is produced by a processcomprising melt processing a mixture of a base resin and a peroxidecompound in a twin screw extrusion system at a temperature in a rangefrom about 120 to about 300° C. to generate peroxide groups at about10-400 ppm of peroxide groups based on the weight of the base resin. 9.The polymer of claim 1, wherein the ethylene polymer is anethylene/l-butene copolymer, an ethylene/l-hexene copolymer, or anethylene/l-octene copolymer.
 10. An article comprising the ethylenepolymer of claim
 1. 11. A blow molded article comprising the ethylenepolymer of claim
 1. 12. An ethylene polymer comprising a highermolecular weight component and a lower molecular weight component,wherein the ethylene polymer has a density of greater than or equal toabout 0.95 g/cm³, a melt index (MI) of less than or equal to about 1.5g/10 min, a ratio of high load melt index to melt index (HLMI/MI) in arange from about 40 to about 175, a peak molecular weight (Mp) of thehigher molecular weight component in a range from about 650,000 to about1,100,000 g/mol, a Mp of the lower molecular weight component in a rangefrom about 40,000 to about 80,000 g/mol, less than about 0.008 longchain branches per 1000 total carbon atoms, a non-conventional comonomerdistribution, and a ratio of Mw/Mn in a range from about 5 to about 18.13. The polymer of claim 12, wherein the lower molecular weightcomponent has: a ratio of Mz/Mw in a range from about 1.5 to about 2.8;a Mp in a range from about 45,000 to about 75,000 g/mol; a Mw in a rangefrom about 50,000 to about 80,000 g/mol; and a Mn in a range from about10,000 to about 30,000 g/mol.
 14. The polymer of claim 12, wherein thehigher molecular weight component has: a ratio of Mz/Mw in a range fromabout 1.5 to about 2.5; a Mp in a range from about 700,000 to about1,100,000 g/mol; a Mw in a range from about 825,000 to about 1,500,000g/mol; and a Mn in a range from about 175,000 to about 700,000 g/mol.15. The polymer of claim 12, wherein the ethylene polymer has: a densityin a range from about 0.95 to about 0.965 g/cm³; a HLMI in a range fromabout 15 to about 100 g/10 min; an ESCR (100% igepal) of at least 1000hours; and an ESCR (10% igepal) of at least 200 hours.
 16. The polymerof claim 15, wherein the ethylene polymer has: a ratio of Mw/Mn in arange from about 6 to about 16; and less than or equal to about 22 wt %of the higher molecular weight component.
 17. The polymer of claim 16,wherein the ethylene polymer has: a melt index in a range from about 0.2to about 0.9.
 18. The polymer of claim 12, wherein the ethylene polymeris an ethylene/1-butene copolymer, an ethylene/1-hexene copolymer, or anethylene/1-octene copolymer.
 19. An article comprising the ethylenepolymer of claim
 12. 20. A blow molded article comprising the ethylenepolymer of claim
 12. 21. An ethylene polymer comprising a highermolecular weight component and a lower molecular weight component,wherein the ethylene polymer has a density of greater than or equal toabout 0.95 g/cm³, a melt index (MI) of less than or equal to about 1.5g/10 min, a ratio of high load melt index to melt index (HLMI/MI) in arange from about 40 to about 175, and a slope of a plot of the viscosity(Pa-sec) versus shear rate (sec⁻¹) at 190° C. of the ethylene polymer at100 sec⁻¹ in a range from about 0.42 to about 0.65, and wherein thelower molecular weight component has a ratio of Mz/Mw in a range fromabout 1.5 to about 2.8.
 22. The polymer of claim 21, wherein theethylene polymer has: a density in a range from about 0.95 to about0.965 g/cm³; an ESCR (100% igepal) of at least 1000 hours; and an ESCR(10% igepal) of at least 200 hours.
 23. The polymer of claim 22, whereinthe ethylene polymer is an ethylene/1-butene copolymer, anethylene/1-hexene copolymer, or an ethylene/1-octene copolymer.
 24. Ablow molded article comprising the ethylene polymer of claim
 23. 25. Anethylene polymer comprising a higher molecular weight component and alower molecular weight component, wherein the ethylene polymer has adensity of greater than or equal to about 0.95 g/cm³, a melt index (MI)of less than or equal to about 1.5 g/10 min, a ratio of high load meltindex to melt index (HLMI/MI) in a range from about 40 to about 175, apeak molecular weight (Mp) of the higher molecular weight component in arange from about 650,000 to about 1,100,000 g/mol, a Mp of the lowermolecular weight component in a range from about 40,000 to about 80,000g/mol, a ratio of Mz/Mw of the lower molecular weight component in arange from about 1.5 to about 2.8, and a ratio of Mw/Mn in a range fromabout 5 to about
 18. 26. The polymer of claim 25, wherein the ethylenepolymer has: a density in a range from about 0.95 to about 0.965 g/cm³;an ESCR (100% igepal) of at least 1000 hours; and an ESCR (10% igepal)of at least 200 hours.
 27. The polymer of claim 26, wherein the ethylenepolymer is an ethylene/1-butene copolymer, an ethylene/1-hexenecopolymer, or an ethylene/1-octene copolymer.
 28. A blow molded articlecomprising the ethylene polymer of claim 27.